Ninetailed

Ninetailed (now Contentful Personalization) is an API-first personalization and experimentation platform for content-rich applications. It provides a REST-based Experience API for managing visitor profiles, defining audience segments, running A/B tests, and delivering personalized experiences at the edge. SDKs are available for JavaScript, React, Next.js, Node.js, and React Native.

Ninetailed publishes 2 API contracts indexed on the APIs.io network: Events API and Profiles API. Tagged areas include Personalization, Experimentation, A/B Testing, Audience Segmentation, and Feature Flags.

The Ninetailed catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Ninetailed’s developer surface includes documentation, engineering blog, pricing, changelog, and 14 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

36.3/100 thin ▬ flat Agent 22/100 agent aware Heartbeat 50/100 alive saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessPaid

1 published contract

Personalization Experimentation A/B Testing Audience Segmentation Feature Flags Edge Computing Content Management

What this lets a business do 1

Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →

Customer Relationship Management

BC-420

Profiles

POST /profiles

Kin Score

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

Composite quality — 36.3/100 · thin

Contract Quality 11.2 / 19

Developer Ergonomics 1.2 / 15

Access Clarity 3.2 / 15

Operational Transparency 3.9 / 10

Contract Governance 0.9 / 9

Discoverability 5.0 / 8

Regulatory Posture 3.2 / 15

Create-or-Update Ergonomics 2.2 / 10

Agent readiness — 22/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 7 / 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 applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% 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):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Machine-Readable Auth +10 pts — a served openid-configuration/oauth-authorization-server carrying `issuer` (served), else the securitySchemes class in the provider OpenAPIs — bound (mutualTLS, DPoP, Signature) > negotiable (oauth2 authorizationCode/clientCredentials, openIdConnect) > bearer (http bearer, apiKey)
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)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document

9 more unmet checks in the Agent Readiness table above.

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

Developer Ergonomics scores 8.3 — up to +18.3 composite points
Access Clarity scores 21.1 — up to +15.8 composite points
Contract Governance scores 9.8 — up to +10.8 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/ninetailed/apis.yml: open an issue on github.com/api-evangelist/ninetailed 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 →

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.

OpenAPI

measured — observed by APIs.io (published)

APIs 2

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

Ninetailed Events API

Batch event ingestion endpoints for profile enrichment.

Ninetailed Profiles API

Operations for creating, reading, updating, and deleting visitor profiles.

Open Collections 2

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Ninetailed Experience Events API

OPEN COLLECTION

Ninetailed Experience Events Profiles API

OPEN COLLECTION

Ninetailed API pricing

Not yet checked against Ninetailed's own pricing page. Compiled by API Evangelist on 2026-06-13; confirm before you rely on a figure.

Plan	Price
Start Paid	—
Core Paid	—
Scale Paid	—

Plan details, limits and sources →

Pricing Plans 1

Published pricing tiers and plan structures.

Ninetailed Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Ninetailed Rate Limits

4 limits

RATE LIMITS

Service Levels 1

Uptime the provider promises or reports, as SLA4OAI. Read from its own pages; APIs.io runs no monitors.

Ninetailed

SLA

FinOps 1

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

Ninetailed Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Ninetailed Context

10 classes · 39 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Ninetailed — jsonschema rules

5 rules · 3 warnings 2 info

SPECTRAL

JSON Schema 3

Standalone JSON Schema definitions for this provider's data models.

NinetailedEvent

7 properties

JSON SCHEMA

NinetailedExperience

4 properties

JSON SCHEMA

NinetailedProfile

9 properties

JSON SCHEMA

Examples 3

Example request and response payloads for these APIs.

Batch Events Sync

4 fields

EXAMPLE

Create Profile

4 fields

EXAMPLE

Update Profile Identify

4 fields

EXAMPLE

Security Posture 3

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

Ninetailed Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Ninetailed Vulnerability Disclosure

security.txt · contact published

SECURITY

Ninetailed Trust Center

SOC 2, ISO 27001

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Ninetailed Agentic Access

6 operations · 5 acting

AGENTIC

Resources

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 2

SDKs, sample code, and the tooling you integrate with

PostmanWorkspace

PostmanWorkspace

GitHubOrg

GitHubOrg

Access & Security 3

Authentication, authorization, and security posture

TrustCenter

TrustCenter

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

StatusPage

StatusPage

ChangeLog

ChangeLog

RateLimits

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

Plans

Plans

FinOps

FinOps

Company 3

The organization behind the API

Website

Website

LinkedIn

Blog

Blog

Other 2

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Source (apis.yml)

aid: ninetailed
name: Ninetailed
description: Ninetailed (now Contentful Personalization) is an API-first personalization and experimentation platform for
  content-rich applications. It provides a REST-based Experience API for managing visitor profiles, defining audience segments,
  running A/B tests, and delivering personalized experiences at the edge. SDKs are available for JavaScript, React, Next.js,
  Node.js, and React Native.
type: Index
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: low
  source:
  - plans
  - security
  generated: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/ninetailed.png
url: https://raw.githubusercontent.com/api-evangelist/ninetailed/refs/heads/main/apis.yml
created: '2026-06-13'
modified: '2026-06-13'
specificationVersion: '0.23'
tags:
- Personalization
- Experimentation
- A/B Testing
- Audience Segmentation
- Feature Flags
- Edge Computing
- Content Management
apis:
- aid: ninetailed:ninetailed-events-api
  name: Ninetailed Events API
  description: Batch event ingestion endpoints for profile enrichment.
  humanURL: https://www.contentful.com/developers/docs/ninetailed/experience-api/
  baseURL: https://experience.ninetailed.co/v2
  tags:
  - Event
  tags_raw:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/ninetailed-events-api-openapi.yml
  - type: Documentation
    url: https://www.contentful.com/developers/docs/ninetailed/experience-api/
- aid: ninetailed:ninetailed-profiles-api
  name: Ninetailed Profiles API
  description: Operations for creating, reading, updating, and deleting visitor profiles.
  humanURL: https://www.contentful.com/developers/docs/ninetailed/experience-api/
  baseURL: https://experience.ninetailed.co/v2
  tags:
  - Profiles
  properties:
  - type: OpenAPI
    url: openapi/ninetailed-profiles-api-openapi.yml
  - type: Documentation
    url: https://www.contentful.com/developers/docs/ninetailed/experience-api/
common:
- type: PostmanWorkspace
  url: https://www.postman.com/kinlaneapi/ninetailed/overview
- type: CapabilityMap
  url: capabilities/ninetailed-capability-edges.yml
  name: Ninetailed Business Capability Map
- type: AgenticAccess
  url: agentic-access/ninetailed-agentic-access.yml
- type: TrustCenter
  url: security/ninetailed-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/ninetailed-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/ninetailed-domain-security.yml
- type: Website
  url: https://www.contentful.com/products/personalization/
- type: Documentation
  url: https://www.contentful.com/developers/docs/ninetailed/
- type: GitHubOrg
  url: https://github.com/ninetailed-inc
- type: LinkedIn
  url: https://www.linkedin.com/company/ninetailed
- type: Blog
  url: https://medium.com/@Ninetailed
- type: Pricing
  url: https://www.contentful.com/pricing/
- type: StatusPage
  url: https://ninetailedstatus.com/
- type: X
  url: https://x.com/ninetailedhq
- type: ChangeLog
  url: https://www.contentful.com/developers/docs/ninetailed/ninetailed-changelog/
- type: Plans
  url: plans/ninetailed-plans-pricing.yml
- type: RateLimits
  url: rate-limits/ninetailed-rate-limits.yml
- type: FinOps
  url: finops/ninetailed-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-parent: contentful
x-relationship: product
x-tags-removed:
- Headless CMS

Ninetailed API — frequently asked questions

Does Ninetailed have an API?

Yes. APIs.io lists 2 APIs from Ninetailed, including Ninetailed Events API and Ninetailed Profiles API.

Is there an OpenAPI specification for the Ninetailed API?

Yes. APIs.io indexes 2 OpenAPI specifications for Ninetailed, each linked for download from this page.

How much does the Ninetailed API cost?

APIs.io lists 3 pricing plans for Ninetailed, with each plan's price, limits and inclusions under Pricing on this page.

Is the Ninetailed API ready for AI agents?

Ninetailed has a Kin Score of 36.3 out of 100 (thin) and an Agent Readiness score of 22.1 (agent-aware), scored by API Evangelist on 2026-11-06.

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