Peer39

Peer39 is a contextual advertising and intelligence company that provides pre-bid controls and post-buy analytics built on verified contextual data for programmatic media buyers. Its platform delivers contextual targeting, brand safety and suitability, and contextual analytics across web, mobile, and connected TV (CTV) and video environments, helping advertisers and platforms make privacy-forward, cookieless media decisions. Peer39 was surfaced as a portfolio company of Canaan Partners and added to the API Evangelist network. Peer39 does operate a real REST API — the Peer39 External API at https://app.peer39.com/api/external — for creating, updating and deleting Custom Categories (contextual targeting and brand-safety lists of keywords, URLs, mobile apps and CTV apps) and syncing them to connected DSPs such as The Trade Desk, Microsoft Advertising/Xandr, Basis, Yahoo and Amazon. That API is entirely undocumented in public: there is no developer portal, no API reference page, no OpenAPI specification and no published SDK. Credentials are provisioned by a Peer39 account or integration manager who grants the "External API" and "RTB Buyer" roles on a named account, and API documentation is distributed as PDFs rather than published on the web. A first-party-authored MCP server for the API exists in pre-release on a personal GitHub account and is the only public description of the surface.

Peer39 publishes 1 API on the APIs.io network. Tagged areas include Company, Contextual Advertising, AdTech, Brand Safety, and Programmatic Advertising.

Peer39’s developer surface includes engineering blog, getting-started guide, signup flow, support, and 9 more developer resources.

🌐 Visit website 📡 Source on GitHub

21.2/100 emerging ▬ flat Agent 8/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessEnterprise

1 APIs 1 MCP Servers

Company Contextual Advertising AdTech Brand Safety Programmatic Advertising Contextual Targeting CTV MarTech Advertising Custom Categories DSP

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 21.2/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 6.2 / 20

Access Clarity 6.8 / 20

Operational Transparency 0.0 / 13

Contract Governance 0.5 / 12

Discoverability 7.6 / 10

Agent readiness — 8/100 · agent aware

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/peer39: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

Peer39 External API

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 pa...

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

Peer39 Custom Category MCP Server

MCP SERVER

Pricing Plans 1

Published pricing tiers and plan structures.

Peer39 Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Peer39 Rate Limits

0 limits

RATE LIMITS

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Peer39 Authentication

2 schemes

SECURITY

Peer39 Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

Login

SignUp

SignUp

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Conformance

Conformance

Build 1

SDKs, sample code, and the tooling you integrate with

Packages

Packages

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 3

Pricing, plans, and the legal terms of use

Plans

Plans

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: peer39
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: enterprise
  onboarding: sales
  trial: false
  try_now: false
  public: false
  label: Enterprise / Contact Sales
  confidence: high
  source:
  - https://www.peer39.com/platform-demo
  - https://www.peer39.com/contact-us
  generated: '2026-08-12'
  method: searched
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/peer39.png
name: Peer39
description: 'Peer39 is a contextual advertising and intelligence company that provides pre-bid controls and post-buy analytics
  built on verified contextual data for programmatic media buyers. Its platform delivers contextual targeting, brand safety
  and suitability, and contextual analytics across web, mobile, and connected TV (CTV) and video environments, helping advertisers
  and platforms make privacy-forward, cookieless media decisions. Peer39 was surfaced as a portfolio company of Canaan Partners
  and added to the API Evangelist network. Peer39 does operate a real REST API — the Peer39 External API at https://app.peer39.com/api/external
  — for creating, updating and deleting Custom Categories (contextual targeting and brand-safety lists of keywords, URLs,
  mobile apps and CTV apps) and syncing them to connected DSPs such as The Trade Desk, Microsoft Advertising/Xandr, Basis,
  Yahoo and Amazon. That API is entirely undocumented in public: there is no developer portal, no API reference page, no OpenAPI
  specification and no published SDK. Credentials are provisioned by a Peer39 account or integration manager who grants the
  "External API" and "RTB Buyer" roles on a named account, and API documentation is distributed as PDFs rather than published
  on the web. A first-party-authored MCP server for the API exists in pre-release on a personal GitHub account and is the
  only public description of the surface.'
url: https://raw.githubusercontent.com/api-evangelist/peer39/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- canaan-partners
x-tier: profiled
x-tier-reason: enrichment-pipeline
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-08-12'
tags:
- Company
- Contextual Advertising
- AdTech
- Brand Safety
- Programmatic Advertising
- Contextual Targeting
- CTV
- MarTech
- Advertising
- Custom Categories
- DSP
apis:
- aid: peer39-external-api
  name: Peer39 External API
  description: '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.'
  humanURL: https://app.peer39.com
  baseURL: https://app.peer39.com
  tags:
  - Contextual Targeting
  - Brand Safety
  - Custom Categories
  - AdTech
  - DSP
  properties:
  - type: Authentication
    url: authentication/peer39-authentication.yml
  - type: Conventions
    url: conventions/peer39-conventions.yml
  - type: ErrorCatalog
    url: errors/peer39-problem-types.yml
  - type: DataModel
    url: data-model/peer39-data-model.yml
  - type: Lifecycle
    url: lifecycle/peer39-lifecycle.yml
  - type: RateLimits
    url: rate-limits/peer39-rate-limits.yml
  - type: MCPServer
    url: mcp/peer39-mcp.yml
  - type: ToolCrosswalk
    url: mcp/peer39-tool-crosswalk.yml
  - type: Login
    url: https://app.peer39.com/login
common:
- type: DomainSecurity
  url: security/peer39-domain-security.yml
- type: LLMsTxt
  url: llms/peer39-llms.txt
- type: Packages
  url: packages/peer39-packages.yml
- type: Conformance
  url: conformance/peer39-conformance.yml
- type: Plans
  url: plans/peer39-plans-pricing.yml
- type: Website
  url: https://www.peer39.com
- type: Blog
  url: https://www.peer39.com/blog
- type: GettingStarted
  url: https://www.peer39.com/onboarding-guide
- type: Login
  url: https://app.peer39.com/login
- type: SignUp
  url: https://www.peer39.com/signup/
- type: Support
  url: https://www.peer39.com/contact-us
- type: TermsOfService
  url: https://www.peer39.com/service-terms
- type: PrivacyPolicy
  url: https://www.peer39.com/privacy-policy/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-08-12'
  status: enriched
  artifacts_added: 12
  pass: local-v1

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