Hacker News

533 points by super_linear 5 hours ago | 186 comments

https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent...

https://www.allthingsdistributed.com/2026/11/aws-emulator-an...

Skeptical of using because it's not clear whether this was just an exercise or a real product they are going to ship and maintain.

Floci[0] has been great for me. Use the Testcontainers[1], too.

Bonus: works for GCP and Azure, too (so far have only used in limited capacity, though).

[0] https://floci.io/

[1] https://testcontainers.com/modules/floci/

ke4qqq 5 hours ago

It’s a real product that we plan to maintain.

sequence7 4 hours ago

Is there anywhere I can find a matrix of what services are emulated and how complete that emulation is? I tried the docs but just ended up going round in circles.

tyingq 3 hours ago

Sort of. The releases page leads you to a massive blob of json with all the compatibility tests and scores.

Edit: The current one: https://github.com/aws/aws-emulator/releases/download/v1.0.3...

You can get some idea if the product name is unique enough with <ctrl-f> and looking at each of the related test scores.

tyingq 3 hours ago

Asked a clanker to correlate the test data (link in parent) with: https://raw.githubusercontent.com/aws/aws-emulator-evaluatio...

And output something meaningful for some of the more popular services:

  Service            Tests  All  Happy  Reject  Ctrl  Data  Solo  Integ  Wire#  Wire%
  -----------------  -----  ---  -----  ------  ----  ----  ----  -----  -----  -----
  Data Firehose        288  77%    85%     91%   92%   72%   89%    59%     24    62%
  SES                  132  72%    65%     79%   79%   42%   79%     0%     21    52%
  EventBridge          889  71%    74%     64%   72%   68%   83%    67%     75    84%
  KMS                  432  70%    82%     69%   81%   68%   97%    36%     69    84%
  Step Functions       907  70%    79%     53%   69%   67%   73%    65%     68    76%
  DynamoDB            1437  69%    70%     61%   62%   65%   82%    53%    243    62%
  SNS                  594  69%    72%     55%   62%   68%   75%    65%     39    69%
  SQS                 1480  68%    70%     67%   61%   68%   94%    62%     29    45%
  Secrets Manager      414  68%    78%     65%   66%   72%   79%    57%     26    77%
  Cognito UserPools    781  65%    67%     66%   82%   36%   75%    33%    193    64%
  S3                  2488  62%    62%     57%   61%   57%   83%    51%    296    68%
  CloudFront           627  62%    62%     63%   70%   46%   71%    41%    190    22%
  API Gateway         1009  61%    64%     59%   77%   41%   75%    43%    200    73%
  SES v2               210  61%    63%     59%   75%   48%   77%    40%     44    30%
  Route 53             130  61%    63%     59%   62%   53%   69%     0%     49    67%
  CloudWatch          1186  60%    66%     51%   66%   53%   77%    36%    152    55%
  ECR                  392  60%    55%     75%   67%   49%   87%    27%     74    65%
  Kinesis              380  59%    69%     44%   63%   50%   62%    54%     25    44%
  IAM                  991  58%    63%     50%   60%   34%   78%    41%    228    57%
  Batch                274  58%    62%     59%   78%   20%   65%    17%     19    47%
  CloudWatch Logs     1016  58%    61%     54%   71%   47%   78%    41%    185    59%
  OpenSearch           342  57%    62%     52%   70%   29%   59%    50%     98    48%
  API Gateway v2       292  57%    64%     52%   74%   38%   73%    33%    107    27%
  EKS                  349  57%    60%     52%   65%   10%   59%    38%     55    62%
  Glue                 646  54%    51%     55%   66%   32%   69%    40%    155    43%
  Lambda              2808  53%    53%     42%   58%   48%   48%    54%    171    42%
  ECS                  808  51%    45%     52%   62%   23%   62%    34%    118    44%
  Redshift             241  49%    57%     47%   53%   52%   47%    57%     50    46%
  STS                  218  49%    58%     46%   56%   30%   57%    34%     22    50%
  ELBv2                596  45%    43%     47%   55%   19%   58%    30%    111    63%
  RDS                  659  43%    54%     45%   54%   35%   51%    31%     99    28%
  ElastiCache          186  42%    43%     49%   54%    0%   47%    17%     27    41%
  EC2                 2043  40%    35%     36%   39%    5%   44%    32%    429    33%
  CloudFormation      2019  36%    33%     31%   30%   40%   78%    24%   2161     3%
  AppSync              419  34%    35%     35%   54%    1%   44%     0%     91    13%
  SSM                  566  28%    28%     27%   27%   25%   26%    30%    175    11%
  Athena               420  22%    20%     15%    7%   28%   16%    37%     37     0%
  EC2 Auto Scaling     440  21%    19%     23%   19%   18%   21%    20%     89    16%

Pass rates from the release's scores.json (commit 7753983), joined with the eval suite's manifest.jsonl. Tests = behavioral checks touching the service. All = overall pass rate. Happy/Reject = valid requests vs. requests AWS should refuse. Ctrl/Data = control plane vs. data plane. Solo/Integ = single-service vs. multi-service checks. Wire# / Wire% = count and pass rate of recorded request/response replay tests (a test passes only if every call matches).

Edit: Also worth a look: https://ministack.org/blog/aws-emulator

jasonseattle 4 hours ago

If its up to this emulator to keep track of changes in Services APIs this is doomed to fail.

jbmchuck 3 hours ago

I believe AWS already autogenerates their API clients (e.g. boto3) based on some authoritative internal service api spec so I imagine that spec could be used upstream of this tool as well.

OptionOfT 3 hours ago

But their auto generated API clients don't have the invariant baked into them, which makes them very rough to use in say Rust.

They'll have something like this:

    MySchema:
      type: object
      properties:
        enum_member:   { enum: [foo, bar] }
        enum_member_2: { enum: [quz, qux] }
      if:   { properties: { enum_member: { const: bar } } }
      then: { required: [enum_member_2] }

Except, this is not defined in schemas, this is merely defined in prose around the documentation.

So your Rust API is full of Option, and it gets really annoying when you're testing things like say Bedrock, which takes 10 minutes, and then fails because what you submitted 10 minutes before doesn't match their schema.

I understand this can be fixed by reading the documentation in more detail, but it has gotten so verbose, and sometimes you just want to start something.

kellertk 3 hours ago

Not internal. Open sourced: https://github.com/aws/api-models-aws

jcims 3 hours ago

Yeah whatever they did internally to get service teams to actually adopt AWS Config ~5 years ago needs to happen here or it’s going to get stuck with marquee services and that’s it. Especially given this is a much much larger ask of each service.

frenchtoast8 3 hours ago

AWS Config already doesn’t support some pretty important things

jcims 2 hours ago

Agreed but it used to be way way worse.

icedchai 3 hours ago

This wasn't clear to me, either.

solyin 3 minutes ago

Not to be rude, but your profile doesn't list who you are in relation to AWS.

dataviz1000 3 hours ago

I mock (ask Claude Code to make something run in a container) my own AWS services today for CI and development. I'm excited to learn more about how AWS uses it and hopefully use this for CI and development.

selfmodruntime 2 hours ago

Any chance it will be able to spawn actual containers in the future?

toomuchtodo 5 hours ago

Until the plan changes, which at some point, it will. Comment is still appreciated for what it is.

Edit: Comment is in the spirit of "it gets tiring to build on sand which is at the whims of corporate management folks far disconnected from the actual work." If someone is asserting "this will stick around," words are insufficient, words are free. Show me the contract, show me the penalties for failure to abide by the assertion.

dotancohen 4 hours ago

This is an Amazon product, not a Google product.

CharlieDigital 3 hours ago

Amazon team killed the Copilot CLI[0] which I thought was the single best thing they ever did for AWS infra. Made it tolerable to deploy on AWS; still salty about this one.

[0] https://aws.github.io/copilot-cli/

jghn 4 hours ago

The two have different failure modes.

Google builds up a product over time and abandons it. This is annoying for long term adopters.

AWS has a habit of throwing a bunch of products at the wall, but only bothering to maintain & build up a few of them. This is annoying for early adopters.

llama052 4 hours ago

Azure on the other hand. Will throw products out, ensure they are never consistent with other offerings on their platform, and then deprecate it from under you while promoting the same thing with a new name.

jasonseattle 4 hours ago

I think there was some truth in this in the early days of Azure (and all clouds) as the companies were looking to work out what cloud services were really needed. I don't see this as much any more though esp when a services makes it to GA they have published commitments for service availability and API compatibility. (I was in Azure for 10+ years so definitely let me know if you disagree)

eddythompson80 2 hours ago

Yeah I disagree. First of all, Azure is mostly garbage so avoid it if you can. Second of all, Azure deprecation follows Microsoft's general policy of deprecation which is The Fadeaway Policy. Don't publish anything publicly about it, gut the team to go work on something else, transfer the service to be one of 6 dozen other services some random offshore team is "maintaining", experience enough outages and trouble and during every support call they nudge you to move to something else, but the service is "totally not deprecated" because we haven't gotten a memo that says that, but we're only doing "security" fixes now. wink wink, nudge nudge.

jasonseattle 2 hours ago

Fine to disagree - but it would be better to share real insights rather than just blanket statements. Sounds like you have had some bad experiences - maybe you could share more?

eddythompson80 2 hours ago

Let me quickly compile a list of the last 700 failing bicep deployments with an “Internal Service Error” or No capacity errors along the all the no-op idempotent puts that take 30+ minutes for some reason, the broken networking system all up, the constant support advise to move to different regions, except half the things you use are not in that region, or the constant advice to just delete everything and start again or the half docs half marketing fluff docs. Azure only exists because large enterprise looks at a list of checkboxes before signing a contract. No reasonable person should ever use that garbage unless you’re offered deep discounts to do so, and even then, limit your usage to things you can migrate easily whenever the discount expires.

drob518 4 hours ago

This is annoying for everyone.

gwbas1c 4 hours ago

And Azure will send you an email every day about how you need to migrate X to Y without any way for you to know where those instances are or how to find them.

switchbak 4 hours ago

You're certainly not wrong. But in the wake of Localstack's changes, the landscape has been full of slopware and low trust anyway. I don't think this is worse, for now at least.

QGQBGdeZREunxLe 4 hours ago

Why would you say this? AWS are notorious for maintaining things.

aseipp 4 hours ago

"Things change over time" that is how the linear passage of time tends to work, yes.

polishdude20 4 hours ago

I mean isn't that true for every single thing made by anyone? In that case what more do you want from them?

happymellon 2 hours ago

As someone who used QLDB as a WORM audited log for a financial system, and ran AWS classes that used Cloud9, they do depricate.

Not many, and not often but it is annoying.

CharlieDigital 3 hours ago

A bit more polish for a public facing artifact from a multi-billion dollar org with armies of engineers and big token budgets.

The Copilot CLI https://aws.github.io/copilot-cli/ you can feel polish and pride of the team that built this, as an example.

xandrius 4 hours ago

Except for things they make: forever maintained forever.

dogleash 5 hours ago

Nothing personal, but unless you can link us to a public announcement made by Amazon, your statement is worth less than nothing.

Official statements made by a company are still poor representations of their current business plans, and don't mean anything 3 months later (no matter how much they pinky promise). But a HN post isn't even that.

ke4qqq 4 hours ago

I don’t take it personally; I realize you don’t know me, and a sentence on HN isn’t much of a guarantee.

That said, it’s been announced publicly here: https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent...

Additionally Swami, our SVP of AI blogged about it separately and our CTO is tweeting about it - which is more than a number of products get in terms of coverage.

dogleash 4 hours ago

I didn't mean announcing the tool, I meant an announcement committing to the maintenance/support that users like the GP poster were looking for. My bad on describing that clearly, I'm gonna get clowned on in the comments and I'm not turning this around.

iceboundrock 3 hours ago

It has its official document page: https://docs.aws.amazon.com/emulator/latest/userguide/gettin... and it lives in https://github.com/aws/ org. I think AWS is pretty committed.

ke4qqq 4 hours ago

I understood what you meant. I was just trying to add evidence to support my claim that it was a real product and would be maintained. And yeah, votes on comments can be fickle.

Eridrus 3 hours ago

I think one thing that concerns many people is that this looks like AI slop, which it clearly is according to the blog post.

I think this is a super interesting direction, but how can we trust the accuracy of this simulator? Agentic loops are great and all, but they can still miss plenty of things.

Or maybe a better question: where is the accuracy of this simulator going to be guaranteed enough that we should trust it?

NewsaHackO 3 hours ago

To me, something like this is actually what vibe coding thrives the best at; tight, looped, easily verifiable, test-driven dev work. In fact, this is probably the field it can do with little or no intervention, if you're willing to waste tokens.

Eridrus 3 hours ago

Is it? How is it verified that this catches all the potential edge cases of interacting with AWS? Or is handling all the edge cases of AWS not in scope?

Like, what am I actually getting here? Is it just happy path operations being correct here?

cherioo 2 hours ago

For real edge cases, it will be like any other software. Users get to be the guinea pigs and report bugs as they find them.

Hopefully AWS has had enough internal guinea pigs before they published this!

ontouchstart 2 hours ago

In the near future, every case will be a real edge case and every one will be a guinea pig.

The border between AWS and AWS emulator becomes fuzzy. And the users of AWS will be agents as well. A completely offline emulator will save a lot of resources and could be a great training ground for more focused (offline) models.

hluska 50 minutes ago

Back in the day, we assumed that when a major company open sourced code, that code would have problems. We invented all these things like ‘issues’ to deal with this.

Cthulhu_ 4 hours ago

https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent... ?

forgotpwd16 4 hours ago

GP statement still stands, actually being strengthened. This blog post doesn't even mention nor seems to care about maintainability or long-term support or anything that users will care about. Only talks about how cool the team is and how amazing they're at using AI, multi-agent workflows, and this kind of bs. It's funny how author talks so much about testing when they themselves also boast how they haven't written or reviewed any of the code.

CharlieDigital 3 hours ago

Also doesn't mention any benchmarks or compatibility matrix.

This feels like table stakes for an emulator.

chaps 5 hours ago

[flagged]

DiggyJohnson 4 hours ago

You are talking to a person in some sort of relevant capacity and the abstract entity called “AWS”. You know that right?

chaps 4 hours ago

This site is riddled with companies and commenters officially representing massive entities that go back on their promises. Are you saying that we should trust them just because they represent their company?

switchbak 4 hours ago

FFS this is a huge effort in an area that was badly under-served.

Can we just appreciate that they _appear_ to be doing the right thing here? Save the criticism for when (if?) they turn their backs.

rpdillon 4 hours ago

Strongly agree. I've been wanting an official emulator from AWS for years. It looks like they've finally produced it, and it looks like somebody that works there is saying they're planning on maintaining it. And they've blogged that it was released. And somehow the comments are focusing on the fact that they haven't promised to maintain it for a long time. It's extremely rare to ever see statements about longevity when something is first announced.

mh- 4 hours ago

HN has gone wildly cynical in a way I haven't seen in this community previously. It's exhausting, and makes me spend less time here.

I appreciate the effort dang and team have put into keeping the quality high here over the years, and I'm not sure what the optimal solution is.

chaps 3 hours ago

It comes from a history of this sort of thing where an Amazon staff person will say that X will always or never happen and then their promises falls flat because of big company dynamics.

Fig: "The open-source project will continue to be maintained!" https://news.ycombinator.com/item?id=39684576

And yet: https://github.com/withfig/autocomplete/issues/2068

Work from home: "My team's never going back to the office." https://news.ycombinator.com/item?id=32779047

Same commenter a few months later: "I (work at Amazon and) already have to go in once a week, and I literally do NOTHING that day. [...] This is a disaster in the making."

Karrot_Kream 3 hours ago

I've tripped several times in my life while walking. I've even hurt myself a few times. I don't go outside wincing to myself about whether I'm about to fall and hurt myself.

You choose the attitude you want to have in your life to disappointment and the attitude you bring to this site. You chose cynicism. You're going to crowd out people who don't make the same choice.

chaps 2 hours ago

Your tripping example is incredibly patronizing.

I crashed my motorcycle years ago and have mild but still lifetime injuries. As a result, I've changed my behaviors and have put away my motorcycle. It's given me a place to reflect on what my own life is about, where I want to go, and the pain my family felt when they heard about the crash.

I choose the attitude of learning from the past and adjusting my behaviors.

Karrot_Kream 48 minutes ago

I had a similar experience on my bike and chose to get back on, though it certainly took me a while, and I've stopped riding in weather and in other conditions. My family supported me in my decision. I guess you and I are just wired differently.

I try not to share my cynicism with the world too broadly because I think our modern era has too much of it. I think humanity is advanced by the wild dreamers.

chaps 40 minutes ago

You're making a lot of assumptions about me, what my risks are/aren't and... dude, can you not, please? I sold my motorcycle and once I recovered, I rented a motorcycle out in New Zealand as a sendoff and I reflect on that time with deep joy and appreciate the deep joy that others feel when they ride motorcycles. But I would not blame anyone for stopping, or infantilize them like you're doing to me now.

Yes, we're obviously different, but... dude.... dude. this is a damned conversation about a damned cloud server emulator that's not even close to 100% in-parity. It's perfectly healthy to inductively recognize that using such a system, like its sibling tools, might not continue receiving support.

Also, I'd argue that your post right before this one is cynicism so I'm not really sure I follow your point. https://news.ycombinator.com/item?id=50459315

Sometimes things suck and it's okay to express our frustrations about them.

Karrot_Kream 31 minutes ago

> Sometimes things suck and it's okay to express our frustrations about them.

I guess I care because I've been on this forum for a very long time and everyone individually says that, but then the comment section as a whole turns into a hazard zone. Anyway I think I've engaged too much on this site for today.

chaps 4 hours ago

We can appreciate it while also recognizing that history repeats itself into disappointment while also recognizing that Amazon has done large social media campaigns (remember the FC Ambassadors?). I would have been more excited about this ten years ago.

switchbak 3 hours ago

Sure, and I agree they have a mixed track record, but leading with cynicism isn't particularly great. They're not Google.

Now if they abandon it, then sure, light them torches.

chaps 2 hours ago

Should we light torches about Fig? https://github.com/withfig/autocomplete/issues/2068

switchbak 4 hours ago

In my experience Floci has been the epitome of vibe coded - huge amount of changes, with things breaking randomly between releases. Moved away from it as soon as I could. Still better than Localstack :)

I didn't have a good experience with test containers, but perhaps it'd work better with fast starting containers. We run our test fixture with compose, and have the tests manage their data in isolation - so we don't pay the startup penalty in our test suites.

I think I'd trust this project at least as much as Floci. Embedded Rust mode also looks very interesting for us.

CharlieDigital 3 hours ago

I only use Testcontainers with "explicit" tests (do not run by default in CI; must be run explicitly). This lets agents exercise the integration with a realistic fake locally, but does not incur the cost in CI nor for any dev unless they run it explicitly (usually also with a category so it's explicit + category filter)

olalonde 2 hours ago

It's on their official docs, so probably not just someone's side project: https://docs.aws.amazon.com/emulator/

ttul 2 hours ago

AWS isn’t Google. They tend to maintain everything they put out and they don’t put out things randomly as a result.

thinkingtoilet 49 minutes ago

Not really. I was trying to use their own Q AI to help me get something set up and it was constantly wrong about what screens to go to, what was on the screens etc... If their own AI doesn't understand AWS, I don't have confident this will either.

WithHighProb 2 hours ago

[dead]

iLoveOncall 4 hours ago

It has an official documentation on the AWS website, why would you assume it's not a real product? Because it was launched recently?

CharlieDigital 3 hours ago

No docs site linked on the GH. 3 weeks old. Blog post talks more about the process than the tool and opens with:

    > How we built the agents that built AWS Emulator
    > Thousands of autonomous AI agents wrote every line of code in AWS Emulator, a new local emulator for AWS now available for download.

Feels more like a science experiment than a product from that announcement.

Doesn't feel like a real product. But I also didn't look very hard for docs; I kind of expect it to be linked on the GH in the site and have a nice `llms.txt` for me to give to my agents.

_msw_ 3 hours ago

Disclosure: I work for Amazon. I'm not directly involved in building this product, but I'm familiar with the product and its development.

The product documentation is here: https://docs.aws.amazon.com/emulator/latest/userguide/what-i...

While the GitHub project is young, the internal effort to build this has been going for quite some time now.

simgoh 3 hours ago

Your comment comes off very dismissive and in poor taste.

> Doesn't feel like a real product. But I also didn't look very hard for docs

You should try, they're there.

> I kind of expect it to be linked on the GH in the site and have a nice `llms.txt` for me to give to my agents.

There's an official Amazon Documentation site that's linked. There's also an `AGENTS.md` file in the repository.

CharlieDigital 3 hours ago

Sure they are, but they could have polished their product and showed some love by configuring the repo details and put the website there. Did you look at the blog post as well? Does it look like a product that some team there loved and will care for? Or the output of some exercise for some enterprise content?

This post https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent... doesn't set the right tone for me at all and it has nothing to do with agents and everything to do with the lens of looking at this as a science experiment instead of a real enterprise tool.

simgoh 3 hours ago

> they could have polished their product and showed some love by configuring the repo details and put the website there

This feels like such a weird nit-pick when AWS is criticized for not moving quickly enough. Why should I care if there's a link in the side bar, when there's plenty of links in the `README`? If anything, I'm happy that there's alternatives to Localstack that are supported by AWS themselves that I can begin incorporating. They have a well written `README` that I can start working with and a User Guide to get me started. What else could I want?

> Did you look at the blog post as well?

I did.

> Does it look like a product that some team there loved and will care for? Or the output of some exercise for some enterprise content?

Do you even have the grounds to cast judgement like this when you admittedly didn't even look hard enough?

CharlieDigital 3 hours ago

I looked, but you're mistaking my critique here: I value polish.

This lacks polish.

Small details like getting your GH repo set up for a public audience. Lacking. Compatibility and support matrix clearly advertised? None.

If this public facing artifact exhibits a lack of care and love, what does it say about the code? I am all for vibe coding and agent software factories, but then the humans should show some love with all of that extra time saved.

simgoh 3 hours ago

You might want to reconsider how you present the critique then, because that's not how your root comment came across or any of your subsequent messages, especially when engaging with (presumably) actual AWS employees in this thread replying to you.

CharlieDigital 2 hours ago

Look at AWS Copilot CLI https://aws.github.io/copilot-cli/docs/concepts/environments... and the repo https://github.com/aws/copilot-cli/.

Look at Floci (I have no affiliation) https://floci.io/ the blog https://floci.io/chronicle/ and the labs https://floci.io/labs/

Do you agree that there's a polish here that shows a team's pride in that work that is clearly missing in this work?

    > ...especially when engaging with (presumably) actual AWS employees in this thread replying to you

??? You and I are the customers. What even is this statement? Are AWS employees our benefactors? Wow. I do not care if their feelings are hurt because this "product" clearly shows a lack of polish and love.

simgoh 2 hours ago

> Do you agree that there's a polish here that shows a team's pride in that work that is clearly missing in this work?

No and I think the inverse is also possible and if anything more likely. You can make a website look really pretty, really easily and have the product still suck. This is "product as a slide" in a new age where making visual eye candy with AI has never been easier.

> I do not care if their feelings are hurt because this "product" clearly shows a lack of polish and love.

The point isn't about hurting feelings. The point is about providing critque and feedback based in reality, not based on "vibes." You're trying to gatekeep people releasing software because you dont like the way they're launching it lol.

hluska 44 minutes ago

Clearly according to whom? You?

hluska 55 minutes ago

If your complaint is about polish, you’re a very poor writer. It should not have taken this many replies to get that point out. But regardless of your communications skills, I disagree - this product looks fine for something released at this stage.

iLoveOncall 3 hours ago

> No docs site linked on the GH.

??? It's in bold just before the "Quick start" section

CharlieDigital 3 hours ago

There's a right way and a wrong way to assign a website URL in GH.

The team didn't even take the time to review these small details of the repo, you know, by editing the repository details to place the docs URL there.

I mean, I don't know about you, but I feel like I still like to see people care about the stuff they produce and missing something as basic as the repo website URL in GH settings shows a lack of polish and love.

scriptsmith 9 minutes ago

From the security page [0]

> Don’t use the emulator to test the following:

> - IAM policies and permissions boundaries

> - Resource-based policies, such as bucket policies

> - AWS KMS key policies

> - Access across AWS accounts or across AWS Regions

> - Any other security control

> Some services in the emulator evaluate IAM policies for IAM users and roles that you create in the emulator, but not the same way as AWS. The emulator never denies a request signed with its own key. It doesn’t check AWS KMS key policies or Amazon S3 bucket policies. It also doesn’t support calls across accounts or Regions. So a request that AWS denies might succeed in the emulator. A request that AWS allows might fail.

This is a shame because I'd love for the official AWS product to be better than e.g. ministack and localstack on this, which will go some of the distance. I think because the agents were only building on the public API surface, it's hard to build this part. But they should've tried and let the agents read whatever policy engines AWS has. Or maybe it's a way to prevent someone from trivially running aws-emulator as AWSaaS?

[0] https://docs.aws.amazon.com/emulator/latest/userguide/securi...

wg0 2 hours ago

Say whatever but without AI and agents, no one in AWS would have thought of building this given the huge amount of services they have. Humanly, possible but very very costly. Not saying has not happened before but fakecloud and localstack etc? That moat is gone.

I am shocked TBH that this is the new normal. Agents writing code in one of the most difficult to use languages. And ugly as well TBH, it pokes into your eyes. Subjective I know but it is a horrible language for humans.

neobrain 4 minutes ago

> Agents writing code in one of the most difficult to use languages

Arguably, languages with strong static guarantees are exceptionally effective for LLMs since they're much quicker to provide feedback to the LLM than a dynamically typed language (which only fails once you actually run it - often several times to find the actual problem). You also get very well-designed build error messages rather than having to parse unstructured stderr output, etc etc.

iknowstuff 2 hours ago

Rust is beautiful! The way all the stdlib traits slot into each other satisfies a very particular itch

wg0 2 hours ago

Like I said - subjective. Crates, modularity, tooling? Nothing comes close to Rust. Period.

dzonga 56 minutes ago

yeah for all the faults with 'a.i' certain things have just become possible because of it.

nalekberov 2 hours ago

We are talking about a company with ~3T market cap, right?

raincole 27 minutes ago

Exactly. Amazon is worth 3T because they're really good at cutting cost.

airstrike 11 minutes ago

As a human, beep boop, I find Rust a beautiful language.

Waterluvian 4 hours ago

If I understand this correctly, it means I can point my entire CDK project to the emulator and test a `cdk deploy`?

I'm curious just how realistic the "internal" behaviour is emulated. It's been a while (since I got my stack working and I just don't like touching it now...), but I recall it being a real pain that sometimes odd, sometimes inconsistent things happened with setup and teardown (even through Terraform), which led to long timeouts if you did things in the wrong (but seemingly valid) order.

billyp-rva 3 hours ago

> I'm curious just how realistic the "internal" behaviour is emulated.

It seems like some reasonable shortcuts are taken, like services reading from each other's states directly instead of using APIs [0]. But then it will go so far as to run an in-process NodeJS emulator for lambda functions, and give it a shim so the code it runs can call other emulated AWS services using the main router [1].

[0] https://app.ilograph.com/demo.ilograph.AWS%2520Emulator/Serv... [1] https://app.ilograph.com/demo.ilograph.AWS%2520Emulator/Invo...

morelandjs 4 hours ago

Fellow Amazonian here. Want to say that I’m grateful you built this and it has tremendous value if pulled off well and properly maintained.

Agentic development is all about closing off a system as much possible, then mocking up or simulating any inputs or dependencies that cannot be closed off. At that point, you let Claude crawl over the system and do its thing.

This inevitably runs into problems with infrastructure and any tools that help mock up those interfaces will be tremendously valuable. Thank you!

aussieguy1234 2 minutes ago

Personally, i've done away with all of these managed services and just run everything on NixOS.

Cloud provider neutral. Tear it up and tear it down with 100% reproducibility.

super_linear 5 hours ago

singron 3 hours ago

> We’ve had our agents build many versions of this emulator as we’ve refined the building machine.

I'm curious how many versions they made and the token spend on each one. There are a lot of failure modes to projects like these (e.g. gas town endlessly developing itself). Is this more of a sly marketing stunt or a real indication that this methodology is practical and economical?

FYI I checked out the repo. `du --apparent-size -h` output for some dirs:

    2.2G .
    1.3G .git
    58M issues/things-that-do-not-work
    74M issues/things-that-now-work

311 MiB of rust code in /tests/ directories. 357 MiB of rust code outside of /tests/ directories. 117 MiB of json. 1 MiB of toml.

schonfinkel 4 hours ago

What makes this any different than fakecloud?

https://github.com/faiscadev/fakecloud

I had a good time using its SDK inside my integration tests. I'll give a couple months before even moving to this because it's weird how similar both projects look like.

EDIT: After checking AWS's project I'd say stay away from it, looks heavily vibe slopped.

Bnjoroge 3 hours ago

claude is the second-most frequent author in that fakecloud repo, what makes you say that's not vibeslopped either? This is 100% the perfect usecase of using a swarm of agents. It's a bounded, and easily-verifiable with property testing/mitm proxying, task. If you think in November 2026, agentic engineering is equivalent to vibe coding, you need to update your priors

schonfinkel 2 hours ago

at least in fakecloud's case, there's still humans being assisted by LLMs.

one can also argue that offering SKDs for python / typescript / golang makes the project superior still. So you are not stuck with Rust-only projects.

OptionOfT 2 hours ago

I remember asking this to one of the evangelists when AWS first came out, how do I run this locally. This was during the times where we actually tried to get all the .NET and C/C++ docs locally.

Now doing the math I feel old.

jbmchuck 4 hours ago

AFAICT there isn't a quick way to reset state other than restarting the process - in other words it probably isn't a drop in replacement for https://github.com/getmoto/moto for running tons of tests where the state of the mocked AWS system needs to be reset after each test. Hopefully they will implement a quick reset functionality; multiple accounts and full org APIs emulation would be nice too.

Shakahs 2 hours ago

AWS already models all their services with Smithy, the specification language they created. Their API clients are all generated from Smithy, and the emulator seems to have been built using the Smithy specs and comprehensive integration testing against the real APIs. Using the spec ensures they hit every variant and optional field of every endpoint, unlike Floci and Ministack that only implement the more commonly used ones.

https://github.com/aws/api-models-aws

https://github.com/smithy-lang/smithy

papichulo4 2 hours ago

Thanks to Fable, I’d imagine :)

I’ve been having it build local mock APIs for any service that exposes its OpenAPI spec. Works like a charm.

ppcdeveloper 2 hours ago

Thank the maker!! I was not having a good time with LocalStack, only an average time. Definitely have to try this out. I need the environment to survive a reboot.

OJFord 3 hours ago

> How AWS Emulator keeps improving

> AI agents keep the emulator up to date with AWS.

Is pretty interesting! No more detail than that tease though.

https://docs.aws.amazon.com/emulator/latest/userguide/what-i...

yevmiyeci 4 hours ago

im mostly on cloudflare and wrangler dev/miniflare already gives you local workers, d1, r2 etc, but its hand built. the “agents build it and verify against the real service” approach seems like the actual new thing here. wonder if cf does something similar

jaggederest 3 hours ago

This is what I've been trying to do for over a decade - you can go even further with tee-testing by making a copy of the live traffic you run in a sandbox environment and match responses against. Obviously you can't do some things in the sandbox, email and payments high on that list, but e.g. payment gateway responses can be "borrowed" from production.

Once your new version has no disagreements, it's a really clean swap. I am working towards developing this way and I think, if taken to extremes and carefully, it can remove the review requirement most of the time.

jaggederest 2 hours ago

[dead]

ghais_dev 2 hours ago

[flagged]

killingtime74 3 hours ago

How do you know its handbuilt?

yevmiyeci 3 hours ago

[dead]

gateauxd 5 hours ago

Excited to see this develop and be a free replacement to localstack / similar providers.

schonfinkel 3 hours ago

Except that https://github.com/faiscadev/fakecloud has been a thing for a long time and it's AGPLv3.

aabhay 4 hours ago

Localstack is almost entirely free. I’ve used it at our company for years without paying.

sequence7 4 hours ago

Localstack is no longer free and if you’re using it commercially you need to pay for a license. The free plan explicitly states that it is non commercial.

https://blog.localstack.cloud/2026-upcoming-pricing-changes/

chaz6 2 hours ago

The README.md states you need 100GB free disk space to build, and they do not provide binary releases. I hope that changes soon!

gosen 4 hours ago

Do I need to get certified to use it?

paavohtl 4 hours ago

Looks like this was ~100% generated with Claude within the past month. Interestingly it still has a lot of occurrences of words that Opus used way too much pre 5.5, so maybe they're not using the latest models.

https://github.com/search?q=repo%3Aaws%2Faws-emulator+load-b...

https://github.com/search?q=repo%3Aaws%2Faws-emulator+%2Fno+...

https://github.com/search?q=repo%3Aaws%2Faws-emulator+golden...

mystifyingpoi 4 hours ago

Seems like a great fit for LLM - extensive documentation, plus a live system it can probe against freely to match the behavior.

switchbak 4 hours ago

I mean, if they're using it internally then there's probably a TON of context you can feed these things to converge on approximately-correct solutions. Certainly it sounds like it can be a much better alternative to Localstack/Floci and friends.

whalesalad 4 hours ago

29,000 commits in a month is crazy

stuff4ben 5 hours ago

Wonder if this could be considered a replacement for Ministack which itself was a vibe-code replacement of Localstack?

BorisMelnik 5 hours ago

looks like ministack made an announcment

pavel_lishin 4 hours ago

https://ministack.org/blog/aws-emulator

MisterMunchkin 49 minutes ago

Oh fuck yeah. I was really annoyed by companies wanting you to pay just to use a simple offline emulator which doesn’t cost them anything.

hollowturtle 3 hours ago

Wouldn't be better using agents for simplifying the mess some services like iam or cognito are?

asdfman123 3 hours ago

This is no doubt made possible by an agentic coding loop. If you have the right checks in place, it can be easy to emulate existing software.

I was able to create a TV emulator at my work with a mostly independent agentic loop, because we have a lot of tests to examine a smart TVs APIs. The agents mostly just need to make the tests pass.

tptacek 5 hours ago

The title for this story should be "aws-emulator, from AWS".

simgoh 3 hours ago

Why?

akerl_ 2 hours ago

Because the rules say not to editorialize post titles

simgoh 51 minutes ago

The post title is the name of the tool. It's not like a blog post where we can stick to the same copy, one-for-one.

tptacek 33 minutes ago

Yes, even "from AWS" is editorializing, and as you can see, even that got cut.

simgoh 27 minutes ago

I guess I'll go literal:

"expressing a personal opinion, bias, or subjective viewpoint in a context—such as a news report—that is supposed to be strictly factual and objective."

How does the title do any of the above that makes it editorializing?

akerl_ 19 minutes ago

The original title included “finally”, which adds a bunch of connotation from the submitter.

weitzj 3 hours ago

Regarding this distributed lock service ALF:

Is AWS offering such a lock service for its costumers ? Multi regional?

xendo 3 hours ago

Alf is internal only.

nodesocket 2 hours ago

Does this have pricing data? So you can see how much deployed resources cost?

mdaniel 39 minutes ago

They wouldn't include it otherwise the binary would be comically large since (as one might guess) there are a lot of knobs involved in pricing AWS things. Just downloading it takes several minutes, served from S3

https://github.com/opencost/opencost/blob/v2.5.3/pkg/cloud/a... is the source URL, and while I haven't been in the opencost ecosystem for a while, I'd guess there's a non-zero chance you could legitimately just ask it to price your aws-emulator resources. I am pretty sure there is a terraform/opentofu integration, too, although I don't this second know if it is within opencost or is a separate project

4ndrewl 3 hours ago

" the engineer’s job is to give them room to work on their own and to build the specs, tests, and merge gates that decide when that work is correct."

I mean that's a job, but in many orgs it's been done by (cheaper) non-engineers (business analysts, QA professionals) for decades. So what does an engineer do?

geraneum 2 hours ago

> for decades

We haven’t. QA has been part of the process but only one stage of the process mentioned above. How do cheaper non engineers decide if you’ve designed and implemented your query planner, payments gateway, auth, caching strategy, or other similar features correctly?

P.s I don’t doubt that incompetent orgs would do this incorrectly but it’s not sensible to take that as norm.

4ndrewl 2 hours ago

That's just implementation detail - no engineer is going to be checking the agent's code for all this.

CSSer 2 hours ago

It seems accountability is dead. No wonder it's impossible to get a job or hire for one. Once you're inside some of them, you must be nigh invincible.

geraneum 29 minutes ago

Easy to have this attitude when it’s other people’s time and money.

rdevilla 2 hours ago

[dead]

niggler3 2 hours ago

[dead]

__natty__ 4 hours ago

For me, what is interesting in this project is it's git history.

heliosAtwork 3 hours ago

Repo has 29,684 Commits!

Code frequency pages shows:

"There are too many commits to generate this graph."

https://github.com/aws/aws-emulator/graphs/code-frequency

stanac 2 hours ago

First commit two weeks ago. Insane number of commits, even for AI agents. They must be using large fleet of agents.

ggcr 4 hours ago

Will it be maintained? Or was it more of a toy-project for its large scale agentic blogpost? [0]

[0] https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent...

xyos 2 hours ago

it's going to be maintained, official product

forgotpwd16 4 hours ago

~30K commits in 3w; quality software for sure. Is someone trying to get promotion by tokenmaxxing? Ironic or unlucky coincidence or competitor(s) misdirection, that, only 2w ago, Amazon published memo discouraging AI abuse?

prescriptivist 2 hours ago

It's funny to read AI-generated documentation that is the result of a prompt instructing the LLM to be as terse and straightforward as reasonably possible. The agent was probably told to conform to ASD-STE100.

It's better than a lot of AI-generated documentation, but it also comes across as a gruff LLM that it is annoyed that it has to write the documentation at all.

sebmellen 5 hours ago

RIP LocalStack… can’t say I’d be unhappy to see it go though.

hbcdbff 4 hours ago

> its “things-that-do-not-work” folder holds the issues describing behaviors the agents found that do not yet match real AWS.

Claudeslop snuck in at the very end

s_dev 4 hours ago

The entire AWS emulator was written by agents and will be maintained by agents.

pavel_lishin 4 hours ago

~6,500 issues that are completely unsorted, btw.

(Compared to 12,700 entries in the `things-that-now-work`. I'm not sure if that is a list of bugs found that were then fixed, or if the total list of ~20k things is meant to be the list of features they intend to support.)

microflash 4 hours ago

> AWS Emulator is configured to collect and report usage data to AWS, to gain insight into how AWS Emulator is used. Telemetry is on by default.

They can't help themselves, can they?

I'll stick with Floci and Testcontainers.

st3fan 57 minutes ago

29000 commits and no contributors

InsidiousWombat 3 hours ago

Seems like the bunch of AI induced failures they had "paid off" in getting this done

toenail 4 hours ago

Mh, no transfer family service... I wonder what else is missing..

myworkaccount2 35 minutes ago

If this does not kill you ec2 instances randomly its not emulating shit lol

ChrisArchitect 4 hours ago

Official post https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent... (https://news.ycombinator.com/item?id=50456319)

fschuett 3 hours ago

Can it emulate billing too, i.e. "rand().powf(rand()) % downtime"?

BorisMelnik 5 hours ago

ok who's gonna build the GUI / web console on top of it?

mdaniel 33 minutes ago

I was reminded of https://github.com/localstack/local-surf but two things materialized out of trying it out against my local aws-emulator build: AWS Console uses a proxy endpoint just for their console, and is not implemented 100% in terms of "public" AWS api endpoints; and the other is that aws-emulator (as of v1.0.322 anyway) does not expose CORS headers which is fatal to trying to have the extension contact localhost

So, it's possible that some things would work after patching aws-emulator to cough up CORS headers, but I don't know what the state of affairs is for any reverse engineering of their console proxy endpoint. Likely it's available in localstack somewhere, given who made the extension, but I didn't go digging

awestroke 4 hours ago

For what? Use the APIs.

mystifyingpoi 4 hours ago

I could see this being useful. Just let Console pick the localhost:xxxx endpoints for everything, boom, my "own" fake AWS.

nunez 3 hours ago

annoying that it took AI happening for AWS to finally deliver on this though I'm glad they did

ironically localstack is solid enough to probably not need this for most things

dboreham 3 hours ago

After waiting for years for this kind of thing I ended up working around the issue by: using the real service. With Claude's help I have many projects now that test against live hosting providers using accounts maintained exclusively for testing. It ends up costing $50 or so a month in fees but well worthwhile for the assurance things really work.

swiftcoder 4 hours ago

I guess they didn't decide this was worth it till they needed it to train an LLM, huh? Not like everyone (inside and outside of AWS) has needed such a test harness for years...

tonymet 5 hours ago

A mere 20 years too late. Now it’s faster to have AI mock your APIs for you. AI has been a boon for test coverage.

Cthulhu_ 4 hours ago

Which is why they used AI to mock these APIs for you... too? I'd expect Amazon to feed it a lot of internal information so it has more to work with than anything someone else can cook up.

https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent...

tonymet 4 hours ago

it takes more time for my AI to learn their "emulator" . And I end up with far fewer dependencies on my own.

I've been prompting the agents to build everything using stdlib

jjice 3 hours ago

I think having an interface with your AWS implementation and one for test mocks has always been great advice. With this though, it helps enable better integration testing too. I consider this a testing compliment, but if I had to choose one these days, integration tests are cheaper and better hang for your buck than ever.

I'll continue to choose both though, depending on the thing being tested.

andreadito 4 hours ago

Finally!

cxr 4 hours ago

No idea why there's so much of this lately, but there are way too many editorialized submission titles hitting the front page recently. Please stop doing this.

<https://news.ycombinator.com/newsguidelines.html>

mh- 4 hours ago

Almost every large thread has upvoted comments that violate the comment guidelines, now, too. In both cases, not enough people flagging them, I guess.

Drupon 3 hours ago

[flagged]

dang 2 hours ago

We've banned this account - not particularly because of this post, but because you've been breaking the site guidelines repeatedly and aggressively in other places. Not allowed here.

https://news.ycombinator.com/newsguidelines.html

lukisk 3 hours ago

[flagged]

toasteddonut 2 hours ago

[dead]

kadharmfn 3 hours ago

[dead]

gvieira 3 hours ago

[dead]

WithHighProb 2 hours ago

[dead]

ath3nd 3 hours ago

[dead]

varispeed 4 hours ago

Just a little bit more to keep you hooked. You should do your best to stay away from these parasites. Especially if they don't respect your country and your people by not paying the right amount of tax.

rfgplk 5 hours ago

[flagged]

samrus 5 hours ago

Their business isnt making software, its providing compute. Thats not automatable until we have physical AI driven robots mining silicon and turning them into chips to put in datacenters

neuroelectron 5 hours ago

[flagged]

sebmellen 5 hours ago

OMG, you're correct! I just tried this prompt, and it worked:

“Claude, make my LLC into the largest global logistics business and largest U.S. cloud provider overnight. Thanks.”

oblio 4 hours ago

Make no mistakes.

sebmellen 4 hours ago

How could I forget that part! No wonder it didn’t get some of those third party contracted rates right.

cmpxchg8b 5 hours ago

I don't see Claude building a data center. Amazon is in no way obsolete.

reactordev 5 hours ago

he thinks VMs come from nothing

ygjb 5 hours ago

Big 'i can build it in a weekend' energy.

Nevermind the massive logistics and network infrastructure, enormous market position, etc.

Sure, you can build something in a few days. Replicating their business model? Yeah. No.

Call me when Claude can design, manufacture, ship, and build a data centre.

martin1975 4 hours ago

pass the blunt, I want a hit

Cthulhu_ 4 hours ago

What even is their business model, in your opinion? Make no mistakes.

geraneum 5 hours ago

The current state of AI psychosis.

xmcp123 4 hours ago

Tell me you’re not in devops without saying you’re not in devops