# Volley

> Sequence diagrams with the request and response on every arrow

- **Website**: https://volley.sh
- **Uneed Page**: https://www.uneed.best/tool/volley
- **Pricing**: Freemium
- **Category**: Development
- **Tags**: Testing, API & Data, Charts
- **Submitted by**: @wdrans-abcd
- **Launch Date**: 2026-10-22

## About

I've found that a good sequence diagram can solve almost any communication problem in engineering. The ones I kept drawing for API work stopped at "App calls Auth Server", and the reader still had to dig through docs to see what was actually sent. Volley fixes that: every arrow can carry its real request and response payloads, shown inline or in a tray.

Write flows in plain text, or skip the typing: point Stripe, GitHub or any webhook at an inbox and turn the deliveries into a diagram; send customers a recording link and get back a diagram with the failed requests marked, with cookies and tokens stripped in their browser; or drop in a HAR file. You can also diff a recording against the sequence you expected.

It's easy for AI tools to write too, with line-and-column errors, a CLI, an HTTP API and an MCP server. The editor is free with no account; Pro is $9/month for saved diagrams, history and higher capture limits.