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API Documentation That Actually Works

Executable markdown for HTTP API's.

Open source • Beta • Windows & Linux coming soon

Sandman Application Screenshot

Open Source & In Active Development

Open Source

Sandman is completely open source. View the code, contribute features, report bugs, or fork it for your own needs.

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Beta Software

We're actively developing Sandman. Features may change, bugs may exist, and your feedback is crucial for improvement.

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Your API docs are lying to you

API documentation gets outdated the moment you write it. Test collections live in proprietary formats. Integration tests are buried in code nobody reads.

What if your documentation was your test suite? What if it lived in git, executed real requests, and proved itself correct every time?

HTTP client & server in one notebook

Notebook

Notebook-Style Development

Write API workflows as interactive blocks of Lua code. Each block depends on the previous one's state—no time-travel bugs, no mystery failures.

Client & Server

Client & Server Testing

Spin up HTTP servers instantly to test webhooks, mock APIs, or create full request/response cycles—all in the same notebook.

Inspect

Inspect Everything

Every HTTP request and response is automatically captured and inspectable. See exactly what happened at each step of your workflow.

Markdown

Living Documentation

Mix executable code with Markdown explanations. The entire notebook saves as a single Markdown file—perfectly git-friendly, human-readable, and always accurate.

Simple, powerful, git-native

1

Write blocks

Combine Lua code and Markdown in notebook blocks. Make HTTP requests, process responses, set up the next step.

2

Run & inspect

Execute your notebook. See every request, every response, every state change. Debug with full visibility.

3

Commit & share

Your notebook is just Markdown. Commit it to git. Share it with your team. Review it like code. Because it is code.

One tool, many workflows

Living Documentation

Document your endpoints as you build them. Show request/response examples that actually work and prove it.

End-to-End Workflows

Document complete user journeys from authentication to data retrieval. Chain requests together with real state, test multi-step API flows.

API Mocking

Replace external dependencies with mock servers. Test your app offline or against edge cases that are hard to reproduce in production.

Onboarding

New team members run your notebooks and see exactly how your API works. Learning by doing, not guessing from stale docs.

CI/CD Integration

Run your notebooks in CI pipelines. Catch API changes and integration failures before they reach production.

API Exploration

Test third-party APIs interactively. Build up complex workflows step by step, seeing results as you go.

Built for API workflows

Lua scripting — Lightweight, fast, perfect for HTTP workflows
Request inspection — See every header, body, and status code
State management — Each block builds on the previous one's results
Markdown integration — Document what you're testing right alongside the code
Local execution — Your API keys stay on your machine
Version control ready — Plain Markdown files work with any git workflow
Server & client testing — Test both sides of the HTTP conversation
Desktop & CLI — Interactive desktop app for development, CLI for CI/CD pipelines (coming soon)
Cross-platform — macOS available now, Windows & Linux coming soon
Open source — Free, transparent, and community-driven development
Beta software — Actively developed with regular updates and improvements

Why Sandman?

Feature Sandman Postman OpenAPI Docs Jupyter
Executable
Git-friendly ⚠️
Human-readable
HTTP-optimized
State flow control ⚠️
Server capability
Living docs

⚠️ Jupyter: JSON format causes merge conflicts • Postman: Variables available but no sequential block dependencies

Stop writing docs that lie

Start testing with executable notebooks today.

Open source beta software for macOS. Windows, Linux, and CLI coming soon. No account required.

⚠️ This is beta software. Features may change, bugs may exist. We welcome your feedback and contributions!