We open sourced Voiden: an offline API tool where requests live as executable Markdown and are versioned in Git. Its built on Electron and its free.
The original idea and inspiration is to combine the flexibility of Obsidian-style files or Jupyter notebooks with the practicality of curl. Instead of static API request forms, everything in the tool is composed with blocks (endpoint, auth, params, body) that can be added, reused, overridden, and stitched together across plain text markdown files.
Since Open Sourcing, we got 11K installs, a lot of feedback and some committed and opinionated contributors.
A few highlights:
Programmable UI: Building API requests with blocks using slash commands (endpoints, headers, auth, params, etc.).
Reusable blocks: These blocks can be connected to (and reused by) multiple docs. Change a value once, update everywhere. Just like in code when we add an extra logic to an imported method. (In other API clients you would need to duplicate stuff or just use environment variables to substitute.)
Specs, tests, and docs live together in executable Markdown . You can structure APIs, tests, and docs however you want and everything stays executable/runnable in the same place.
Scripting: We have seen other API tools locking scripts into a constrained JS runtime. Voiden runs locally, that means you can use whatever is already on your machine (Node, Python, shell, etc.). So this feels like real scripting and not sandboxes.
Multiple requests per file (mini workflows): Putting multiple requests in a single .void file turned out to be surprisingly useful. You can group full flows together (create-pay-confirm), or full CRUD cycles. The file becomes an executable workflow where docs and tests live together naturally, and you can run one request or the entire sequence end-to-end.
Stitch (workflows across files): Instead of building large monolithic collections, workflows can be composed from smaller .void files. This way, Auth, setup, CRUD, etc. become pieces that can be reused and combined across contexts without duplication. This is still early and evolving.
Agents: Added “skills” so tools like Claude or Codex can work directly with .void files using your own environment and subscriptions. Yeah, one of the perks of everything being file-based and Markdown-first.
We also built an SDK for community plugins and spent time improving performance, reliability, and keyboard-first DX (Electron-based, so we have been careful there).
Happy to hear any feedback, suggestions and contributions!
Github: https://github.com/VoidenHQ/voiden
Download: https://voiden.md/download