> 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:
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.
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)
Do you have any recommendations to start learning cloud infrastructure with a almost real setup? ive heard of localstack but also a lot of negative reviews, so im not sure how to get started..
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.
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.
Nope. Anthropics models did. Amazon is de facto obsolete, anyone with a bit of money and Claude on an API leash can replicate their entire business model, in days.
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
"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?
Hey, I'm one of the MiniStack maintainers. We'll definitely keep maintaining and running MiniStack. We're already well established, with many companies using it, including NVIDIA, NASA, Block, and others.
Until the AWS emulator can match all our current capabilities, such as multi-account, multi-region, IAM, running IaC, etc., we'll still be around
One of our core principles has always been to focus on supporting only the most commonly used services
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.
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.
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.
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
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...
~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?
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.
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.
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.
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.
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!
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.
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.
> 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].
175 comments
[ 129 ms ] story [ 1334 ms ] threadI'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:
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.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/
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.
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.
> 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.
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.
Nope. Anthropics models did. Amazon is de facto obsolete, anyone with a bit of money and Claude on an API leash can replicate their entire business model, in days.
"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?
Until the AWS emulator can match all our current capabilities, such as multi-account, multi-region, IAM, running IaC, etc., we'll still be around
One of our core principles has always been to focus on supporting only the most commonly used services
https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent...
I've been prompting the agents to build everything using stdlib
I'll continue to choose both though, depending on the thing being tested.
https://blog.localstack.cloud/2026-upcoming-pricing-changes/
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
<https://news.ycombinator.com/newsguidelines.html>
sybau
https://news.ycombinator.com/newsguidelines.html
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...
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!
[0] https://www.aboutamazon.com/news/aws/how-autonomous-ai-agent...
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.
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...
Code frequency pages shows:
"There are too many commits to generate this graph."
https://github.com/aws/aws-emulator/graphs/code-frequency
They can't help themselves, can they?
I'll stick with Floci and Testcontainers.