alt.hn

3/31/2026 at 8:48:15 PM

MiniStack (replacement for LocalStack)

 https://ministack.org/

by kerblang

4/1/2026 at 7:18:15 AM

I have detailed knowledge of dynamodb. This code does not properly mimic the service exceptions, input validations, eventual consistency, or edge cases. I would not feel comfortable developing against ministack or running tests against it. A lot of these services also have free tiers, so the use cases are quite minimal.

by arpinum

4/1/2026 at 5:23:29 PM

Hello! The target use case is integration testing, verifying that your application calls the right operations with the right data, not production fidelity. For that, MiniStack works well and is free. For anything requiring exact DynamoDB behavior (capacity throttling, consistency window, stream processing), you're right that it's not a substitute. Contributions to improve error fidelity are very welcome (we have pending ProvisionedThroughputExceededException, TransactionConflictException, ItemCollectionSizeLimitExceededException)

by nnucera

4/1/2026 at 10:38:48 AM

Mostly I think its not about cost, it is about iteration speed and ability to run in CI environments fast.

by justincormack

4/1/2026 at 2:41:58 PM

If your CI DB is not 100% in parity with the real db -- you are setting yourself up for disaster. It is a false sense of security.

Same reason I wince when people say things like "we just use SQLite in tests, but our real db is mysql/psql/etc"

The test results have no merit if they are testing against a glorified mock.

by whalesalad

4/1/2026 at 5:23:02 PM

You could have the fast tests that catch 99,9999% of the issues on feature branches and just run the real slow test before putting in prod.

by victorbjorklund

4/1/2026 at 3:13:35 PM

You can have fast tests and slow. Having fast tests to make progress working on features is important.

by justincormack

4/1/2026 at 8:48:58 PM

I still think it's useful - you can do your base case testing against ministack and only start incurring AWS charges to finalize your load testing.

by commandlinefan

4/1/2026 at 8:24:01 PM

Neither does localstack to be fair.

by Macha

4/1/2026 at 12:48:32 AM

I'm frustrated with the Localstack license changes and will evaluate ministack.

But, for anybody else who needs a quick fix - you can pin to the `community-archive` tag and it should unblock you quickly:

https://hub.docker.com/layers/localstack/localstack/communit...

by philip1209

4/1/2026 at 8:23:50 PM

Thoughts on https://github.com/hectorvent/floci ?

by ksh09

4/2/2026 at 9:43:15 AM

two weeks old project that already emulates 20+ services from AWS that's suspicious (tbf ministack is even worse in that matter)

by Oxodao

3/31/2026 at 10:18:11 PM

I really don't see how any clone is going to manage to do what localstack couldn't - maintain compatibility with tons of AWS services while not getting paid for it. If this were viable, why would it not have worked before?

The only things I can think of are that perhaps LocalStack was just a mess of a codebase that couldn't maintain velocity or attract contributors, or it just failed to steward new contributors or some such thing.

by staticassertion

3/31/2026 at 10:40:57 PM

Hello! We won't have the broad coverage that Localstack has... we're not aiming to be the "next Localstack"... just want to keep the core services that were available for free in the LS community up to date. If you’re looking for larger services like MWAA, sorry, but we won't be supporting them.... Most core AWS services don't receive many updates anyway (their APIs don’t change drastically or frequently)

by nnucera

4/1/2026 at 1:02:01 AM

> We won't have the broad coverage that Localstack has... we're not aiming to be the "next Localstack"

you should tell that to the LLM that writes your website:

> MiniStack is your free, MIT-licensed drop-in replacement.

is it a drop-in replacement, or not?

by evil-olive

4/1/2026 at 1:09:26 AM

If you’re looking for a Localstack alternative, it’s often because you were using the community tier... In that case, Ministack can serve as a drop-in replacement... otherwise, the price reduction in LS might already address your needs

by nnucera

4/1/2026 at 5:15:08 AM

If this were viable, why would it not have worked before?

Because something wasn't in place to make it work. There are millions of examples where the second mover won, often because the first mover was too early, or the tech wasn't there to make it work, or the market didn't understand the value, etc.

In this case I imagine there are three massive benefits that you'd have over being the first mover:

- AWS is more mature and therefore moving slower, so it's easier to keep up.

- AI is useful for building 80% working code, so there's a lot less to do to keep up.

- There's a lot of devs looking for ways to move off Localstack due to the price change, which gives you (potentially) a pool of willing volunteers to contribute to an OSS alternative.

You can also learn from Localstack's open source version about what's needed, what works, what doesn't work, etc.

by onion2k

3/31/2026 at 10:57:00 PM

Personally, I would get value out of really solid compatibility of the base features of a few core services (sqs, s3, kms, and maybe dynamo are the main ones that come to mind) with a light weight gui interface and persistence.

If I’m getting into esoteric features or some “big” features that don’t make sense locally, then I just spin up a real dev account of aws, so I know I’m getting the real experience.

by mikeocool

4/1/2026 at 12:07:06 AM

> getting into esoteric features

The problem is that everybody needs different "core" features

> > compatibility of the base features of a few core services (sqs, s3, kms, and maybe dynamo are the main ones that come to mind)

For instance, I don't care about any of those features at all. But I would care a lot about EC2, RDS, and ElastiCache Redis

by petcat

4/1/2026 at 4:00:30 AM

Interesting — those are the ones that depending on the case, approximating them with local redis/postgres/vms without the AWS specific APIs on top is often good enough — because my app is just talking to them over native protocols anyway.

Or I am doing something so specific, that a local emulation of the aws api isn’t ever going to be good enough, so there’s not a lot of point in trying. For example, writing code that handles automatically spinning up RDS instances from an RDS snapshot — a local emulation of that process is going to be so far off from what would actually happen no matter what they do.

by mikeocool

4/1/2026 at 2:17:07 AM

I'd put ALL the ones listed above: SQS, S3, KMS, DynamoDB, EC2, RDS, Redis in the required "core" services column, and also throw in IAM, SNS, and SecretsManager as well. Those are all table stakes imho.

I'm using all of the above in LocalStack today. Frankly, I don't believe this is as "impossible" a task as several in this thread are insinuating. It's the type of rote work you can delegate to AI to build these days, as observed in this OP.

Building a test suite to validate the state-transient mocks in question against the real deal is not difficult. Only annoyingly expensive (in time and money) if run often, which is exactly the problem they're solving.

by drzaiusx11

3/31/2026 at 10:32:54 PM

"LocalStack was just a mess of a codebase" - very true.

I do think there's potential to semi-automatically create a compatible suite of services, but it'll require some very talented use of LLMs and some novel testing approaches. Not something I want to sign up for.

I evaluated Floci, but that has the typical issues you'd expected with freshly minted vibe code.

by switchbak

4/1/2026 at 5:20:01 AM

idk maybe AWS should create one?

I mean, if we can use "virtual-AWS", it would dramatically lower entry-barrier for devs/companies who are scared of "tales of huge aws bills" and such

by sysguest

4/1/2026 at 2:54:19 PM

I wouldn’t hold my breath. They do have a dynamo db fake, but they don’t even release the code for it! Perhaps they’re concerned about making it really easy to clone their stuff.

But we can still do that ourselves, dynamically interrogating the real thing and comparing it to the fake.

by switchbak

4/1/2026 at 11:06:58 AM

It hasnt really been a barrier to entry though has it, cloud adoption is doing just fine.

by justincormack

4/1/2026 at 4:19:06 AM

That's true if you assume making these things is manual work. But of course with well documented API service and AI coding tools, making a functional local equivalent of any given service is not all that hard.

by jillesvangurp

4/1/2026 at 6:34:13 AM

Cloning the API surface is cheap, but once you try to match edge-case behavior across auth and retries you spend way more time than most weekend projects can justify.

You fake half the error modes or your test rig drfits from prod fast.

by hrmtst93837

4/1/2026 at 11:06:20 AM

I am currently implementing S3, with correct error handling for edge cases. Its been about a month and I have almost the whole API surface done, with some gaps (you actually need a broader surface eg some IAM, KMS encrytion needs a persistence layer so only done sse-c so far). Close to the point where you could drop it in as a local emulation tool, its a sub 9MB binary (Rust).

Literally as I write this the AI code review said "suspended-bucket current-version selection is still wrong when the numbered version and the newer null version land in the same millisecond." - thats the level of detail you have to deal with.

by justincormack

4/1/2026 at 11:45:39 AM

An then the S3 team ships some internal code changes wich results in subtle difference in how the API behaves in edge cases and you "emulator" is wrong again.

by hrmtst93837

4/1/2026 at 3:15:45 PM

Actually no, because they actually have to worry about their millions of customer deployments not randomly breaking every other week. So, they are generally very good about not breaking compatibility unless they have a really good reason to. And when they do, they typically give people years of time to deal with any backwards compatibility breaking changes. Because otherwise they are dealing with lots of support overhead and angry customers. That and the multiple independently developed s3 compatible clients or alternatives make this probably the easiest thing to simulate in the AWS universe as it is probably the most widely used thing in AWS.

by jillesvangurp

4/1/2026 at 1:10:16 PM

Not really, the main thing they could change is the order in which errors are checked when there are multiple errors, but even a lot of that is not likely to change, eg html based stuff comes first. There are actual reasons for a lot of the subtleties, plus they have to have a stable contract for all the success cases as people rely on it. And its not hard to update, I have 800 or so tests against AWS that run in a few minutes.

by justincormack

4/1/2026 at 2:33:02 PM

[dead]

by hrmtst93837

3/31/2026 at 10:35:50 PM

I suppose (among many other things) LLMs are changing this. We no longer need that many contributors when we can use AWS docs, intercept AWS API calls and give it to AI agent to mimic. Of course, contributors are still needed for maintaining tests and validations.

by 4m1rk

3/31/2026 at 10:41:18 PM

and then the maintainer goes on a rant about accurate but agentically coded pull requests and doesn’t merge it

by yieldcrv

4/1/2026 at 2:55:48 AM

The real issue with LocalStack was always drift. Tests pass locally, then something breaks in staging because the S3 response format is slightly different or DynamoDB throttling doesn't match. After getting burned enough times we just switched to short-lived real AWS environments for integration tests. More expensive, but way fewer surprises in prod.

by robshippr

4/1/2026 at 4:30:01 AM

i would imagine localstack is a sniff-test - aka, if it doesn't pass localstack, you don't run the more expensive real AWS integration test. In other words, like food, you don't eat the cost unless it passes the sniff test.

by chii

4/1/2026 at 2:03:25 PM

[dead]

by jamiemallers

4/1/2026 at 5:19:33 AM

[dead]

by tazsat0512

4/1/2026 at 4:22:37 PM

[dead]

by MeetRickAI

4/1/2026 at 12:46:03 AM

Any project with Claude’s signature misaligned ASCII diagram just screams DON’T USE to me. If you can’t even bother to read your damn generated README, how do I know you have QC’ed anything else? At the very least supported features claimed in README / on website could be totally fake, which is extremely common among all the vibed Show HNs.

https://github.com/Nahuel990/ministack/blob/a1b1d20a27d2238d...

by oefrha

4/1/2026 at 5:19:16 AM

I love how a comment pointing out glaring lack of human review of this project (with clear evidence) is flagged to death. With zero counter-argument no less. Can’t wait for the bright future of vibed crap with zero human quality control getting hacked every day.

by oefrha

4/1/2026 at 2:13:26 AM

But brother, he is shipping at inference speed!

by andai

4/1/2026 at 7:33:50 AM

ASCII with rounded corners is already a red flag, let alone not being able to check if it's aligned. Claude LOVES these.

Something more realistic would be:

+-----+

| foo |

+-----+

by ramon156

4/1/2026 at 9:53:51 AM

> ASCII with rounded corners

To be that guy for a moment: those are not ASCII as those characters are not in the standard 7-bit ASCII set. The closest you get to rounded corners with just ASCII is something like:

    /-----\       .-----. 
    | bah |  or   | bah |   (the latter usually looks best IMO, but that can depend on font)
    \-----/       `-----'
You'd get away with calling the linked diagram ANSI. While that is technically incorrect most people accept the term for something that uses one of the common 8-bit character sets that include those box-drawing characters (CP437, CP850, ISO-8859, Win1252, …), because that is what MS has for a long time called Win1252 in its tools.

> is already a red flag

I wouldn't call using box-drawing characters a red flag, I've known people use them this way for years and do so myself. The LLM generates them because they were in its training data because people use them. It might be something to consider amongst other flags but I don't consider it a strong signal on its own. The red flag for me is the alignment - if you are going to have your documentation ghostwritten at least make the effort to do a cursory editing pass afterwards.

by dspillett

4/1/2026 at 2:30:49 AM

Yeah. Could at least run a formatter on it afterwards... You can even configure a hook for Claude to do that.

by arcanemachiner

4/1/2026 at 1:50:51 AM

We live in the golden age of slop. It seems a surprisingly small number of people have the visceral AI disgust response.

by sebmellen

4/1/2026 at 3:39:38 AM

Maybe that visceral response being against the rules (assume good faith) and actively being punished explains the small number of people doing it?

by heliumtera

4/1/2026 at 9:35:26 AM

My visceral AI disgust response here is just a subset of my more general lazyly-slapped-together-without-sufficient-testing-or-other-review disgust response. If it doesn't look bad in that way, whether hand-made or ghostwritten, then I'll not react to it that way. But if someone can't be bothered to do a simple clean-up pass on that documentation, what mess could they have left in the code too?

As far as I'm concerned the social contract (“the rules”) has already been broken by people taking insufficient care, and my reaction to that is a healthy one from the PoV of self-preservation. Acting in good faith works both ways, or it doesn't.

by dspillett

4/1/2026 at 1:59:37 PM

>Acting in good faith works both ways, or it doesn't.

Well said, polluting hacker news with low effort slop for self promotion cannot be good faith. The rules are enforced on commenters but good faith is not expected for submissions somehow

by heliumtera

3/31/2026 at 9:26:09 PM

Ugh, I hadn't heard the news about the LocalStack licensing changes. I had some great results building AWS services for local dev as well as CI/CD and testing in GH actions with LocalStack in previous jobs.

I secretly always hoped Amazon would buy out LocalStack and make it the official free local development environment for AWS work, but I guess it probably would reduce revenues spent on AWS based dev and test environments. The compatibility with the AWS CLI was mostly excellent in my experiences.

by giobox

4/1/2026 at 1:14:54 AM

Unclear what LocalStack's end game is tbh. My company has an active enterprise license atm so their recent changes won't affect me in the short term at least. As of writing I'm still a happy user of LocalStack. Disappointed with their overall direction, but I hold no ill will and I'm sure they had their reasons. I wish them luck.

Hopefully this change was not just an short term attempt to lock in current enterprise customers by shoring up existing income streams. That'll only work in the VERY short term.

It's not difficult to forsee the inevitable customer drain to free competitors or private one-shots easily produced by genai from publicly available AWS SDK code. Maybe they're already feeling that pressure and that's all this change is. I hope not.

AFAICT, they have no appreciable moat to retain customers long term. For example, I have absolutely no interest in their "Pods" or even their console UI, so thosr aren't keeping me around forever. For their sakes I hope they're still shopping themselves around and didn't take some VC poison pill with preconditions for killing the community edition. Really It's anyone's guess though.

by drzaiusx11

4/1/2026 at 12:46:55 AM

> The compatibility with the AWS CLI was mostly excellent in my experiences.

Interesting, I've had the opposite experience. Every single AWS service I've ever tried to build tests around with LocalStack has run into compatibility issues. Usually something works in LocalStack but fails when it hits the real endpoint.

I guess the CLI itself has mostly worked, its more the LocalStack service not behaving the way the real service is documented/works.

by hexedpackets

4/1/2026 at 1:39:26 AM

Got any concrete examples? I've been happily using LocalStack for roughly a decade now and haven't run into a single compatibility issue, aside from the obvious missing of net new services for the first N months after AWS product launches. Things like AppConfig, etc, but those gaps got filled in time. They clearly prioritized the 95pct/most used features of each service first though. There's a long tail in some AWS services, as one might expect. I've never used any of the more esoteric AWS feature sets of any of their services. Those are the things that tend to end up deprecated. So requiring those long tail featur sets may be the simple answer to having very different experiences.

by drzaiusx11

4/1/2026 at 4:17:15 PM

I think it's still very early for this to be adapted in the SDLC, but looks very promising. I am frustrated with Localstack at this point, and this may just do the job.

by techwithprateek

3/31/2026 at 9:53:59 PM

Another alternative, earlier on HN: https://news.ycombinator.com/item?id=47420619

by mikecarlton

3/31/2026 at 10:22:25 PM

I liked the transparency: "Built entirely with AI by Jack Danger | All prompts saved in prompts/"

by cmertayak

3/31/2026 at 10:38:45 PM

Thus far I've tried that (rejected), Floci (not great), and now looking at this.

This one is 7 days old.

I'm eager to have a localstack replacement, but these are a long way off from being mature enough. I suppose this is just the new state of software? Shiny website, big claims, AI coded, insufficiently tested.

by switchbak

3/31/2026 at 11:18:04 PM

Out of curiosity, why did you reject Floci? It lacked some feature I needed, so I just went ahead and added them. My needs were not that complex and it has patterns to test that implementations match AWS. I agree it’s lacking things, but the bones aren’t that bad.

by thegagne

4/1/2026 at 2:51:08 PM

I too added some stuff, but keeping up with the pace of it was annoying. Conflict city, slow reviews made it a headache.

In particular my issues were: - missing range fetches (probably in place now) - Missing version support in various places - bugs wrt to the handling of versioned objects across api calls

My needs are not super mainstream, but I was better off using RustFS in this case. A single lightweight fake would be preferable though.

by switchbak

4/1/2026 at 12:24:30 AM

What’s the gcp equivalent

by threethirtytwo

4/1/2026 at 4:06:22 PM

Hey! GCP has their own set of tools for emulation. IDK why Amazon dont do the same. It would be way easier for everyone

by nnucera

4/1/2026 at 12:37:19 PM

FR: real cost simulator

by opengrass

3/31/2026 at 9:26:26 PM

> Copyright (c) 2024 MiniStack Contributors

Already lying or totally unreviewed AI slop ?

by kay_o

3/31/2026 at 10:08:56 PM

slop copy

by cmertayak

4/1/2026 at 1:48:41 PM

As other commenters have noted, this looks like AI slop. Why is it on the front page?

If you go on Reddit, there are at least a dozen AI "vibe coded" shitty local stack alternatives being posted daily. Whats special about this??

by shantnutiwari

4/1/2026 at 6:57:10 PM

A bunch of these are popping up because LocalStack changed their free tier and people needed something else. This isn’t trying to replace all of LocalStack. Just the basic stuff people were using before, and keep it fast for local dev.. If you care about exact behavior or edge cases you still need real AWS. This is more for quick integration tests so you’re not hitting AWS all the time.

What’s different? IDK, you could try the "dozen AI vibe coded shitty local stack alternatives" and post it on your blog

by nnucera

4/1/2026 at 8:52:26 PM

[dead]

by tomerbd

4/1/2026 at 2:48:57 AM

[dead]

by weiyong1024

3/31/2026 at 10:20:37 PM

[dead]

by redlewel

4/1/2026 at 10:37:32 AM

[dead]

by SophieVeldman

4/1/2026 at 12:19:03 AM

[flagged]

by volume_tech

4/1/2026 at 2:06:12 AM

Drift feels inevitable here. AWS keeps evolving, so any local emulator will eventually diverge. At some point it’s more about how much drift you can tolerate than missing features.

by heyethan

4/1/2026 at 3:32:13 PM

[flagged]

by steffs

4/1/2026 at 6:29:35 PM

AI comments are against the rules

by slopinthebag