AppNexus website screenshot

AppNexus

AppNexus was a New York-based programmatic advertising technology company that ran one of the largest independent real-time online ad exchanges alongside a cloud-based buy-side and sell-side platform for advertisers, agencies, and publishers. AT&T acquired AppNexus in 2018 and rebranded it Xandr; it is now part of Microsoft. Its developer surface lives on as the Xandr Digital Platform API (host api.appnexus.com) - a RESTful JSON API for campaign, creative, inventory, deal, and reporting operations - plus the first-party AppNexus mobile advertising SDKs for Android and iOS. This profile was enriched by the API Evangelist pipeline from the public developer documentation.

AppNexus publishes 1 API on the APIs.io network. Tagged areas include Company, Adtech, Advertising, Programmatic, and Ad Exchange.

AppNexus’ developer surface includes documentation, API reference, getting-started guide, authentication, changelog, sandbox, and 12 more developer resources.

🌐 Visit website 📡 Source on GitHub
24.7/100 emerging ▬ flat Agent 17/100 agent aware Full breakdown ↓
scored 2026-07-28 · rubric v0.5
1 APIs
CompanyAdtechAdvertisingProgrammaticAd ExchangeDSPSSPMobile SDKMarketing

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-28 · rubric v0.5
Composite quality — 24.7/100 · emerging
Contract Quality 0.0 / 25
Developer Ergonomics 11.7 / 20
Commercial Clarity 0.0 / 20
Operational Transparency 3.8 / 13
Governance 0.0 / 12
Discoverability 9.3 / 10
Agent readiness — 17/100 · agent aware
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 15
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 0 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/appnexus: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 1

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

Digital Platform API

RESTful JSON API for the AppNexus/Xandr programmatic advertising platform - manage advertisers, campaigns, line items, creatives, placements, inventory, deals, and pull reportin...

Security Posture 2

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

Appnexus Authentication

token · 1 scheme

SECURITY

Appnexus Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 GettingStarted
GettingStarted
 Sandbox
Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt
LLMsTxt

Design & Contract 3

Pagination, idempotency, versioning, errors, and events

Conventions
Conventions
 ErrorCatalog
ErrorCatalog
 Lifecycle
Lifecycle

Build 4

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 Packages
Packages
 SDKs
SDKs
 SDKs
SDKs

Access & Security 2

Authentication, authorization, and security posture

Authentication
Authentication
 DomainSecurity
DomainSecurity

Operate 2

Status, limits, changes, and where to get help

Deprecation
Deprecation
 ChangeLog
ChangeLog

Company 1

The organization behind the API

Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: appnexus
name: AppNexus
description: AppNexus was a New York-based programmatic advertising technology company that ran one of the largest independent
  real-time online ad exchanges alongside a cloud-based buy-side and sell-side platform for advertisers, agencies, and publishers.
  AT&T acquired AppNexus in 2018 and rebranded it Xandr; it is now part of Microsoft. Its developer surface lives on as the
  Xandr Digital Platform API (host api.appnexus.com) - a RESTful JSON API for campaign, creative, inventory, deal, and reporting
  operations - plus the first-party AppNexus mobile advertising SDKs for Android and iOS. This profile was enriched by the
  API Evangelist pipeline from the public developer documentation.
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://raw.githubusercontent.com/api-evangelist/appnexus/refs/heads/main/apis.yml
url: https://raw.githubusercontent.com/api-evangelist/appnexus/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- first-round-capital
x-tier: stub
x-tier-reason: portfolio-lead
x-successor: xandr
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-17'
tags:
- Company
- Adtech
- Advertising
- Programmatic
- Ad Exchange
- DSP
- SSP
- Mobile SDK
- Marketing
apis:
- name: Digital Platform API
  description: RESTful JSON API for the AppNexus/Xandr programmatic advertising platform - manage advertisers, campaigns,
    line items, creatives, placements, inventory, deals, and pull reporting. Token authentication, offset pagination (start_element/num_elements),
    and a response/error envelope.
  humanURL: https://learn.microsoft.com/xandr/digital-platform-api/
  baseURL: https://api.appnexus.com
  tags:
  - Advertising
  - Programmatic
  - Adtech
  properties:
  - type: Documentation
    url: https://learn.microsoft.com/xandr/digital-platform-api/
  - type: APIReference
    url: https://learn.microsoft.com/xandr/digital-platform-api/api-services
  - type: Authentication
    url: authentication/appnexus-authentication.yml
  - type: Conventions
    url: conventions/appnexus-conventions.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://www.appnexus.com
- type: DeveloperPortal
  url: https://learn.microsoft.com/xandr/digital-platform-api/
- type: Documentation
  url: https://learn.microsoft.com/xandr/digital-platform-api/
- type: APIReference
  url: https://learn.microsoft.com/xandr/digital-platform-api/api-services
- type: GettingStarted
  url: https://learn.microsoft.com/xandr/digital-platform-api/api-onboarding-process
- type: GitHubOrganization
  url: https://github.com/appnexus
- type: Authentication
  url: authentication/appnexus-authentication.yml
- type: Conventions
  url: conventions/appnexus-conventions.yml
- type: ErrorCatalog
  url: errors/appnexus-error-codes.yml
- type: Lifecycle
  url: lifecycle/appnexus-lifecycle.yml
- type: Deprecation
  url: https://learn.microsoft.com/xandr/digital-platform-api/breaking-changes
- type: ChangeLog
  url: https://learn.microsoft.com/xandr/digital-platform-api/api-release-notes
- type: Sandbox
  url: sandbox/appnexus-sandbox.yml
- type: Packages
  url: packages/appnexus-packages.yml
- type: SDKs
  name: AppNexus Android Mobile SDK
  url: packages/appnexus-packages.yml
- type: SDKs
  name: AppNexus iOS Mobile SDK
  url: packages/appnexus-packages.yml
- type: DomainSecurity
  url: security/appnexus-domain-security.yml
- type: LLMsTxt
  url: llms/appnexus-llms.txt
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence