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Appendix

API Reference

REST API for submitting clinical encounters, managing patients, polling physician chat, and reading account state. JSON in, JSON out. This is the API individuals and their personal AI agents use with a personal Appendix account.

Building on the Prescribing API? If your app requests physician reviews for its users, that's a separate contract — its own keys, consent flow, and per-review billing. Start at the Prescribing API overview.

Base URL

https://api.appendix.com

All paths in this reference are relative to that base. Versioned under /api/v1/.

Conventions

  • Content type. Requests and responses are application/json unless otherwise noted (image upload uses multipart).
  • Errors. Non-2xx responses return {"error": "..."} with the HTTP status code carrying the meaning.
  • IDs. UUIDs unless explicitly tokens. Encounter ownership is enforced on every authenticated read — foreign IDs return 404.
  • Timestamps. RFC 3339 / ISO 8601, UTC.

Where to start

Quick Start

POST a letter, get a checkout URL. The five-line version.

Authentication

Anonymous calls, personal API keys, and the auto-submit shortcut for paying subscribers.

Endpoints

Agent

POST/api/v1/agent/queryGET/POST/api/v1/agent/encounters/{id}/events

Encounters

GET/api/v1/encountersGET/api/v1/encounters/{id}GET/api/v1/encounters/{id}/turnsGET/api/v1/encounters/{id}/latest-turnPOST/api/v1/encounters/{id}/cancel

Patients

GET/api/v1/patientsPOST/api/v1/patientsGET/api/v1/patients/{id}PATCH/api/v1/patients/{id}DELETE/api/v1/patients/{id}

Account

GET/api/v1/users/meGET/api/v1/users/me/submissionsPOST/api/v1/users/me/api-keysGET/api/v1/users/me/api-keysDELETE/api/v1/users/me/api-keys/{keyId}

Subscription

GET/api/v1/subscriptions/meGET/api/v1/subscriptions/me/payment-methodGET/api/v1/subscriptions/me/invoices

Knowledge & configuration

GET/api/v1/knowledge/searchGET/api/v1/config/conditionsGET/api/v1/config/pricing