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; Microsoft acquired Xandr in 2022 and productized it as Microsoft Monetize (sell-side) and Microsoft Invest (buy-side). Its developer surface lives on as the Digital Platform API (host api.appnexus.com) - a RESTful JSON API of roughly 150 services covering advertisers, insertion orders, line items, campaigns, creatives, publishers, sites, placements, deals and reporting - plus the actively released AppNexus mobile advertising SDKs for Android and iOS. Microsoft is discontinuing the Invest DSP effective 28 February 2026; the Monetize sell-side platform and the API remain live, documented on Microsoft Learn. No OpenAPI, MCP server or agent card is published, and API access is restricted to contracted customers. This profile was enriched by the API Evangelist pipeline from the public developer documentation.

AppNexus is listed with 1 API on the APIs.io network. Tagged areas include Company, AdTech, Advertising, Programmatic, and Ad Exchange.

AppNexus’ developer surface includes engineering blog, documentation, API reference, getting-started guide, authentication, changelog, support, and 24 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

39.4/100 developing ▬ flat Agent 8/100 agent aware Front door AI 5/6 prominent Heartbeat 68/100 slowing saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 API

Company AdTech Advertising Programmatic Ad Exchange DSP Supply Side Platform Mobile SDK Marketing

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 39.4/100 · developing

Contract Quality 0.0 / 21

Developer Ergonomics 10.9 / 17

Access Clarity 3.6 / 17

Operational Transparency 9.3 / 11

Contract Governance 1.9 / 10

Discoverability 6.2 / 9

Regulatory Posture 4.1 / 15

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

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

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.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Machine-Readable Contract +18 pts — api_specs includes an OpenAPI document
MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link

10 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 0.0 — up to +25.0 composite points
Access Clarity scores 21.1 — up to +15.8 composite points
Contract Governance scores 18.2 — up to +9.8 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

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 the provider profile at artifacts.apis.io/appnexus/apis.yml: open an issue on github.com/api-evangelist/appnexus to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Mobile SDK Publishers (Play SDK Index, CocoaPods, ADA certification)	distribution	9.6 (thin)	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 1

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

Dataspace Protocol

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

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...

AppNexus API pricing

Rate limits

: service defined
: service defined
: 10 5 minutes

All 4 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

Appnexus Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Appnexus Rate Limits

4 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Appnexus Finops

FINOPS

Security Posture 3

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

Appnexus Authentication

token · 2 schemes

SECURITY

Appnexus Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Appnexus Vulnerability Disclosure

Hackerone

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Login

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 6

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

Lifecycle

Components

DataModel

Conformance

Build 5

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

Packages

SDKs

SDKs

SDKs

Access & Security 5

Authentication, authorization, and security posture

Authentication

Authentication

Compliance

Compliance

DomainSecurity

DomainSecurity

VulnerabilityDisclosure

VulnerabilityDisclosure

Security

Security

Operate 6

Status, limits, changes, and where to get help

Deprecation

StatusPage

ChangeLog

ChangeLog

Support

RateLimits

Commercial 1

Pricing, plans, and the legal terms of use

Plans

Plans

Company 2

The organization behind the API

Blog

Blog

Website

Website

Source (apis.yml)

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; Microsoft acquired Xandr in 2022 and productized it as Microsoft
  Monetize (sell-side) and Microsoft Invest (buy-side). Its developer surface lives on as the Digital Platform API (host api.appnexus.com)
  - a RESTful JSON API of roughly 150 services covering advertisers, insertion orders, line items, campaigns, creatives, publishers,
  sites, placements, deals and reporting - plus the actively released AppNexus mobile advertising SDKs for Android and iOS.
  Microsoft is discontinuing the Invest DSP effective 28 February 2026; the Monetize sell-side platform and the API remain
  live, documented on Microsoft Learn. No OpenAPI, MCP server or agent card is published, and API access is restricted to
  contracted customers. This profile was enriched by the API Evangelist pipeline from the public developer documentation.
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: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - plans
  - authentication
  - rate-limits
  - security
  - sandbox
  - url: https://www.appnexus.com
    status: 301
    note: declared website redirects to https://about.ads.microsoft.com/en — a different registrable domain (appnexus.com
      -> microsoft.com), possible rename or acquisition (probed 2026-09-03, roadmap#169)
  generated: '2026-11-06'
  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: '0.23'
created: '2026-07-17'
modified: '2026-10-06'
tags:
- Company
- AdTech
- Advertising
- Programmatic
- Ad Exchange
- DSP
- Supply Side Platform
- Mobile SDK
- Marketing
tags_raw:
- 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
  tags_raw:
  - Advertising
  - Programmatic
  - Adtech
  properties:
  - type: Documentation
    url: https://learn.microsoft.com/xandr/digital-platform-api/
  - type: APIReference
    url: https://learn.microsoft.com/en-us/xandr/digital-platform-api/reference
  - type: Authentication
    url: authentication/appnexus-authentication.yml
  - type: Conventions
    url: conventions/appnexus-conventions.yml
  - type: RateLimits
    url: rate-limits/appnexus-rate-limits.yml
  - type: DataModel
    url: data-model/appnexus-data-model.yml
  - type: ErrorCatalog
    url: errors/appnexus-error-codes.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- url: https://about.ads.microsoft.com/en/resources/discover/insights
  type: Blog
- 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/en-us/xandr/digital-platform-api/reference
- 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/en-us/xandr/digital-platform-api/breaking-changes
- type: StatusPage
  name: Xandr Status
  url: https://status.xandr.com
- type: ChangeLog
  name: Microsoft Monetize release notes
  url: https://learn.microsoft.com/en-us/xandr/monetize/release-notes
- type: ChangeLog
  name: Changelog surfaces (artifact)
  url: changelog/appnexus-changelog.yml
- type: Support
  name: Xandr Customer Support Portal
  url: https://help.xandr.com
- type: Login
  name: Microsoft Monetize console
  url: https://monetize.xandr.com/login
- type: Packages
  url: packages/appnexus-packages.yml
- type: SDKs
  name: anx-api (Digital Platform API JavaScript client)
  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: Components
  url: components/appnexus-components.yml
- type: RateLimits
  url: rate-limits/appnexus-rate-limits.yml
- type: Plans
  url: plans/appnexus-plans-pricing.yml
- type: DataModel
  url: data-model/appnexus-data-model.yml
- type: Conformance
  url: conformance/appnexus-conformance.yml
- type: Compliance
  name: Industry standards bodies Xandr states membership in (IAB Tech Lab, NAI, TAG, Prebid.org, W3C)
  url: conformance/appnexus-conformance.yml
- type: DomainSecurity
  url: security/appnexus-domain-security.yml
- type: VulnerabilityDisclosure
  url: security/appnexus-vulnerability-disclosure.yml
- type: Security
  name: Microsoft Security Response Center (parent-company disclosure channel for Xandr)
  url: security/appnexus-vulnerability-disclosure.yml
- type: LLMsTxt
  url: llms/appnexus-llms.txt
x-pointer-notes:
  withdrawn:
  - type: Sandbox
    reason: Withdrawn 2026-08-12. api-test.appnexus.com appears only inside a curl -v trace in the docs and 404s when probed;
      Xandr publishes no sandbox, test mode or test credentials. See sandbox/appnexus-sandbox.yml.
  not_emitted:
  - type: WellKnown
    reason: Every /.well-known path 404s on api.appnexus.com. www.appnexus.com and www.xandr.com 301 to about.ads.microsoft.com,
      whose SPA answers 200 with an HTML shell for every path - a soft-404, not a document. See well-known/appnexus-well-known.yml.
  - type: AgentCard
    reason: no agent-card.json or agent.json on any host; search-only artifact, nothing written.
  - type: CLI
    reason: anx-cli exists on npm but its only release is 0.1.10 from 2016-03-31 and the current documentation never mentions
      a CLI. Artifact kept at cli/appnexus-cli.yml as an abandonment record; no pointer emitted. See cli/appnexus-cli.yml.
  - type: Idempotency
    reason: no Idempotency-Key contract is documented anywhere in the Digital Platform API.
  - type:
    - OpenAPI
    - AsyncAPI
    - Webhooks
    - MCPServer
    - AgentSkill
    - OAuthScopes
    - Overlay
    - Protobuf
    reason: No machine-readable contract of any kind is published, and there is no event/webhook surface, MCP server or OAuth
      scope model to describe. Skills and overlays have no spec to ground them in.
  - type:
    - Pricing
    - TermsOfService
    - PrivacyPolicy
    reason: Explicitly not public - "The Xandr Service Policies, Privacy Regulations, Platform Terms of Service and Online
      Terms are confidential and tied to specific contracts between Xandr and its customers." See plans/appnexus-plans-pricing.yml.
x-enrichment:
  date: '2026-08-12'
  status: enriched
  artifacts_added: 8
  pass: local-v1

AppNexus API — frequently asked questions

Does AppNexus have an API?

Yes. APIs.io lists 1 API from AppNexus, including Digital Platform API.

How do I authenticate with the AppNexus API?

AppNexus uses bearer-token authentication (token · 2 schemes). The details are profiled on APIs.io as Appnexus Authentication.

Is the AppNexus API ready for AI agents?

AppNexus has a Kin Score of 39.4 out of 100 (developing) and an Agent Readiness score of 7.9 (agent-aware), scored by API Evangelist on 2026-11-06.

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