Let's Encrypt

Let's Encrypt Authorization API

Domain control authorizations

GitHub OpenAPI

Documentation

📖
Documentation
https://letsencrypt.org/docs/

Specifications

⚙
OpenAPI
https://raw.githubusercontent.com/api-evangelist/lets-encrypt/refs/heads/main/openapi/lets-encrypt-authorization-api-openapi.yml

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this
  • find_apisBrowse and filter every API in the catalog.
  • get_api_artifactsOne API's artifacts, grouped by type.
  • get_openapiThe primary OpenAPI for this API.
  • find_similar_apisAPIs that look like this one.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools

Call it yourself

curl for this page
This API 
curl "https://apis.io/api/v1/apis/lets-encrypt-authorization-api"
All apis 
curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no email required.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

lets-encrypt-authorization-api-openapi.yml Raw ↑ 
openapi: 3.0.3
info:
  title: Let's Encrypt ACME Account Authorization API
  description: The ACME (Automatic Certificate Management Environment) protocol API used by Let's Encrypt to automate the issuance, renewal, and revocation of TLS certificates. Implements RFC 8555.
  version: '1.0'
  contact:
    name: Let's Encrypt
    url: https://letsencrypt.org/docs/
  license:
    name: Mozilla Public License 2.0
    url: https://www.mozilla.org/en-US/MPL/2.0/
servers:
- url: https://acme-v02.api.letsencrypt.org
  description: Production ACME endpoint
- url: https://acme-staging-v02.api.letsencrypt.org
  description: Staging ACME endpoint
tags:
- name: Authorization
  description: Domain control authorizations
paths:
  /acme/authz/{authzId}:
    post:
      tags:
      - Authorization
      summary: Get authorization status
      operationId: getAuthorization
      parameters:
      - name: authzId
        in: path
        required: true
        schema:
          type: string
      requestBody:
        required: true
        content:
          application/jose+json:
            schema:
              $ref: '#/components/schemas/JWS'
      responses:
        '200':
          description: Authorization status
components:
  schemas:
    JWS:
      type: object
      description: Flattened JSON Web Signature object per RFC 7515
      properties:
        protected:
          type: string
        payload:
          type: string
        signature:
          type: string