# Developer docs

> Everything you need to build on Evergist: the REST API, the encryption scheme, the MCP server and CLI for agents, the JavaScript module, and OpenAPI.

Source: https://evergist.com/docs/
Updated: 2026-09-29

Evergist is a small API for storing ciphertext, plus clients that do the encryption for you. Start with whichever fits.

## Guides

- [REST API reference](https://evergist.com/docs/api/): endpoints, request and response formats, errors, limits, and a complete Web Crypto example.
- [Encryption scheme](https://evergist.com/security/#the-encryption-scheme): the exact v1 derivation, what the server stores, and how to verify it.
- [Agent guide](https://evergist.com/agents/): set up the MCP server in Claude Code, Codex, Cursor, and other clients, plus the CLI and SKILL.md.

## Downloads and specs

| File | What it is |
|---|---|
| [openapi.json](https://evergist.com/openapi.json) | OpenAPI 3.1 description of the API |
| [evergist.tgz](https://evergist.com/cli/evergist.tgz) | CLI and MCP server as an npm tarball. Run with `npx -y evergist` |
| [evergist.mjs](https://evergist.com/cli/evergist.mjs) | The same CLI as one dependency-free file |
| [evergist.js](https://evergist.com/sdk/evergist.js) | ES module client for Deno, Bun, browsers, and Workers |
| [evergist_read.py](https://evergist.com/examples/evergist_read.py) | Independent Python implementation that reads a note |
| [SKILL.md](https://evergist.com/SKILL.md) | Agent skill with every command and usage rules |
| [llms.txt](https://evergist.com/llms.txt) | Index for language models. [llms-full.txt](https://evergist.com/llms-full.txt) has everything in one file |

## Limits at a glance

| Limit | Value |
|---|---|
| Note size | 512 KiB of UTF-8 text |
| Expiry | 1 minute to 30 days |
| View limit | 1 to 1,000, or none |
| Wrong passwords | 10, then the note is deleted |
| Rate limits | 10 creates per minute and 120 per hour, 120 reads per minute, from one network |

Questions or problems: [contact@evergist.com](mailto:contact@evergist.com).