# Peer39 External API

**Canonical:** https://apis.io/apis/peer39/peer39-external-api/  
**Provider:** Peer39 — https://apis.io/providers/peer39/  
**Base URL:** https://app.peer39.com  
**Documentation:** https://app.peer39.com

Peer39 External API is published by [Peer39](https://apis.io/providers/peer39/) on the [APIs.io](https://apis.io/) network. Tagged areas include Contextual Targeting, Brand Safety, Custom Categories, AdTech, and DSP. The published artifact set on APIs.io includes authentication docs and rate-limit docs.

The Peer39 External API manages Custom Categories — contextual targeting and brand-safety lists of keywords, URLs, mobile apps or CTV apps — and syncs them to a connected DSP partner. Nine operations are known: session login, list/get/create/ full-update/metadata-update/items-update/delete of custom categories, and a URL-example prediction preview. Authentication is a session bearer token obtained by POSTing a username and password to /api/external/login; the account must carry the "External API" and "RTB Buyer" roles, which are granted by a Peer39 integration manager. The API is credential-gated and publicly undocumented — Peer39 publishes no API reference page and no OpenAPI. This profile is derived from Peer39's own publicly readable MCP server source plus live probes of the API host, and every path under /api/external returns HTTP 401 unauthenticated.

## Machine-readable artifacts (10)

- **Authentication** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/authentication/peer39-authentication.yml
- **Conventions** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/conventions/peer39-conventions.yml
- **ErrorCatalog** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/errors/peer39-problem-types.yml
- **DataModel** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/data-model/peer39-data-model.yml
- **Lifecycle** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/lifecycle/peer39-lifecycle.yml
- **RateLimits** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/rate-limits/peer39-rate-limits.yml
- **MCPServer** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/mcp/peer39-mcp.yml
- **ToolCrosswalk** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/mcp/peer39-tool-crosswalk.yml
- **Login** — https://app.peer39.com/login
- **APIsJSON** — https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/apis.yml

## Tags

Contextual Targeting, Brand Safety, Custom Categories, AdTech, DSP

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/peer39/peer39-external-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/peer39/.