Overview

HarperHarbor provides accounts, billing and conversation APIs for companion AI apps. Users sign in with a platform account and use the same wallet across apps they authorize. The platform manages authentication, billing and model connections.

Use Open API v1 for HTTP requests and OAuth 2.1 for user authorization. AI clients can use MCP.

If you are evaluating HarperHarbor for a new app, request access to confirm the services and integration settings you need. This documentation describes the v1 API; service availability and paid plans are confirmed during onboarding.

QuickstartRegister, exchange a code, make your first call.

AuthenticationOAuth 2.1 authorization code with PKCE, dynamic registration, refresh.

Conversation loopStart, stream, rewrite, rewind, save.

API referenceEvery endpoint in the v1 contract, generated from the OpenAPI document.

What v1 covers

Area	What you get
Identity	Who is signed in — public numeric id only
Conversation	Open, resume, stream, rewrite, rewind, save, fork, notepads, directives, memory
Cards	Read a card, per-player settings, the author’s page assets
Authoring	Create and edit private cards, worldbooks, images, publish for review
Trial cards	Temporary private cards imported from local files, with automatic expiry
Models	Catalog with lanes and prices, lane availability

Moderation, payments, analytics and account management are not part of v1 and are not planned for it. Payments happen in the user’s wallet on the platform; see Quotas and pricing.

API conventions

1. No internal identifiers. Responses carry the public numeric user id and opaque resource ids, never account UUIDs.
2. The language header is the locale. Accept-Language is not consulted.
3. Unknown fields are ignorable. New fields and new stream events appear over time; a client that ignores what it does not know keeps working.