Essays and hot takes on testing, AWS, and AI-assisted development.
LocalStack gates ECR behind Pro and `docker push` is flaky for those who pay. Moto ships a control plane but can't speak the OCI v2 Distribution protocol. fakecloud ships both — full 58-op API plus real `docker push`/`pull`, free.
Configure AI coding assistants (Claude Code, Cursor, GitHub Copilot) to use fakecloud for AWS integration tests. Reliable local AWS for agent-assisted development, no account or auth token needed.
Bedrock Guardrails evaluate content policies, PII filters, topic filters, and contextual grounding. Testing a guardrail setup against real AWS is slow and expensive. fakecloud runs the guardrail control plane and the ApplyGuardrail data plane locally, with real content evaluation.
Every AI-team engineer eventually asks: should my Bedrock tests hit a real model? Even a local one like Ollama? Short answer: no. Here's what tests actually need, and what happens when you try to use real inference instead.
Deploy and test AWS CDK apps locally with fakecloud. Full cdklocal flow, plain cdk with AWS_ENDPOINT_URL, CI setup. Free, open-source, no account required.
Run real AWS integration tests in GitHub Actions, GitLab CI, and CircleCI with fakecloud. Copy-paste workflows for SQS, SNS, DynamoDB, Lambda, S3. No account, no auth token, no paid tier.
Four free, open-source alternatives to LocalStack Community: fakecloud, MiniStack, floci, and Moto. What each is architecturally, how they position, and how to pick by fit.
LocalStack supports Bedrock only on their Ultimate plan, and only four operations, all backed by Ollama. Here's what that gets you, what it doesn't, and why fakecloud's approach is different.
Step-by-step migration from LocalStack Community to fakecloud: docker-compose, CI, Terraform, CDK, Serverless Framework. Copy-paste configs for every common setup.
Moto is Python-only. fakecloud is a real HTTP server speaking the AWS wire protocol, so the same thing works for Go, Java, Kotlin, Node.js, Rust, and PHP. Copy-paste examples for each language.
Run Terraform against AWS locally with fakecloud. Provider endpoints config, tflocal, CI setup. Free, open-source, no account required. Works with the upstream terraform-provider-aws TestAcc suites.
Run Lambda locally against a real runtime in seconds. Covers all 13 AWS Lambda runtimes, event source mappings, and cross-service triggers (S3, SQS, SNS, EventBridge). No mocks, no SAM, no account required.
I'd bet most developers are already shipping AI-generated code without properly reviewing it. Not because they have guardrails, but because they're busy and the code looks fine. Here's what I think we should do about it.
AI tools can write AWS code fast, but they hallucinate APIs and create tests that pass while asserting wrong behavior. Here's how to test AI-generated AWS code properly: real integrations, external verification, and guardrails the AI can't game.
Testing code that calls Bedrock is painful: every run burns tokens, hits rate limits, and returns different text. Here's how to test Bedrock-calling code locally against fakecloud — deterministic responses, configurable per prompt, with fault injection for retry logic.
LocalStack went proprietary in March 2026. fakecloud is a free, open-source AWS emulator for integration testing — 20 services, 100% conformance, no auth required.
fakecloud went from zero to 17 AWS services in 6 days using LLMs. Here's how tests, CI, and architecture steering made that possible without shipping garbage.
LocalStack went proprietary. Our builds broke. So I built a free, open-source replacement in Rust — 13 AWS services, 731 API operations, 100% conformance.