# folder.md

> API-first file storage for AI agents and the applications they build.

Folder provides a remote filesystem through REST, MCP, a TypeScript SDK, CLI, and Folder Stack (F-stack). It supports two sibling use cases: persistent agent workspaces and an application file-storage backend. Folder stores files; pair it with Supabase/Postgres, Convex, SQLite/PGlite, or another database for users, relationships, transactions, and application state.

Folder is not a database and does not currently expose an S3-compatible API.

## Start

- [Developer documentation](https://www.folder.md/docs)
- [OpenAPI 3.1](https://www.folder.md/openapi.json)
- [Full LLM reference](https://www.folder.md/llms-full.txt)
- [Live agent capabilities](https://www.folder.md/api/v1/agent/capabilities)
- [Folder Stack installer](https://www.folder.md/fstack/install.sh)

## Canonical endpoints

- API base: https://www.folder.md/api/v1
- MCP package: @foldermd/mcp
- TypeScript SDK: @foldermd/sdk
- CLI package: @foldermd/cli

## Current limits

- Standard API uploads: 100 MB per file, Folder application-layer encryption.
- Direct single-part uploads: just under 5 GiB, subject to Folder quota, R2-managed AES-256 at rest, no Folder application-layer encryption.
- Multipart/resumable uploads: not active.
- Default Folder quota: 1 GB; read storage_limit from the Folder response.
- General API: 100 requests/minute/key; upload initiation: 30/minute/key. Current enforcement is per running instance.