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/

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.

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 and looking at each of the related test scores.

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

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

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.

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.

The documentation is not detailed enough, you need to call the service for detailed correctness.

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

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.

AWS Config already doesn’t support some pretty important things

Agreed but it used to be way way worse.

AWS has lots of unfunded mandates like this and they historically just depended on bleeding the souls of engineers and managers to get done.

I suspect this is built by agents through bleeding the soul of GPUs until it gets too expensive (unfunded mandates are free after all on the OP1/2). Then it just decays into the place all good PR/FAQs decay once their sponsors are promoted, burned out, or are laid off.

KTLO-as-a-Service

There are many AWS services. Simply offering an alternative to a few of the most used could be a good business. It doesn't have to cover all AWS in all release versions, just enough to get and hold some clients

This wasn't clear to me, either.