Proof
#1 in AI Code Review & QAevery · since 2026-03-11 · 53× · last seen Jun 30, 2026
100
Momentum
Proof is an agent-native, collaborative online document editor by Every (every.to), publicly launched on March 11, 2026. It allows humans and AI agents to work simultaneously on Markdown documents, with every character change attributed to its author (human or AI). The product is free and requires no login; the underlying SDK (proof-sdk) was simultaneously open-sourced on GitHub under the MIT license. An Every subscription ($30/month) additionally unlocks a persistent document library.
Momentum trend
04.04.03.07.
Features
| Base Model | Model-agnostic; documented support for Claude Code (Anthropic), ChatGPT (OpenAI), and Codex (OpenAI) via the HTTP agent bridge; no proprietary in-house LLM |
| License | MIT (proof-sdk on GitHub: github.com/EveryInc/proof-sdk); hosted product under proprietary Every terms of use |
| Platform | Web (proofeditor.ai); self-hostable via proof-sdk (Node.js, editor on localhost:3000, API on localhost:4000) |
| Price | Free (no login required, no document library); persistent document library with Every subscription: $30/month or $288/year |
| Release Date | March 11, 2026 (public launch) |
| Interface (IDE/CLI/Web) | Web editor (proofeditor.ai); HTTP agent bridge (/api/bridge/); CLI install via curl for Codex (proof.SKILL.md); compatible with Claude Code, OpenAI Codex, OpenClaw |
| Supported Languages | Markdown (collaborative Markdown editor with provenance tracking); no indication of additional markup languages in official sources |