Affinity

Affinity is a relationship intelligence CRM built for private equity, venture capital, and investment banking teams. It provides a REST API that enables developers to manage contacts, organizations, opportunities, lists, notes, and relationship timelines derived from email and calendar activity. The API is available in two versions: a legacy V1 with full read/write capabilities for persons, companies, opportunities, notes, interactions, reminders, and webhooks, and a modern V2 RESTful interface designed for internal apps, automated workflows, and third-party integrations. API access is included in the Scale, Advanced, and Enterprise subscription tiers, with monthly call limits ranging from 100,000 to unlimited depending on the plan.

Affinity publishes 10 APIs on the APIs.io network, including auth API, companies API, companyMerges API, and 7 more. Tagged areas include CRM, Relationship Intelligence, Private Equity, Venture Capital, and Contacts.

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

Affinity’s developer surface includes authentication, documentation, engineering blog, pricing, and 13 more developer resources.

🌐 Visit website 📡 Source on GitHub

49.2/100 developing ▬ flat Agent 27/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessPaid

1 APIs

CRM Relationship Intelligence Private Equity Venture Capital Contacts Organization Opportunities Deal Management

Kin Score

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

Composite quality — 49.2/100 · developing

Contract Quality 15.2 / 23

Developer Ergonomics 4.3 / 18

Access Clarity 10.4 / 18

Operational Transparency 6.2 / 12

Contract Governance 2.7 / 11

Discoverability 6.2 / 9

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 27/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 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

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.

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/affinity: 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 11

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

Affinity API V1

The legacy Affinity V1 API provides comprehensive read and write access to core CRM data including persons, organizations, opportunities, lists, notes, interactions, reminders, ...

Affinity auth API

Operations about auths

Affinity companies API

Operations about companies

Affinity companyMerges API

Operations about company merges

Affinity emails API

Operations about emails

Affinity lists API

Operations about lists

Affinity meetings API

Operations about meetings

Affinity notes API

Operations about notes

Affinity opportunities API

Operations about opportunities

Affinity personMerges API

Operations about person merges

Affinity persons API

Operations about persons

Scroll for all 11

Open Collections 11

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

API Collection

OPEN COLLECTION

Affinity API v2 auth API

OPEN COLLECTION

Affinity API v2 auth companies API

OPEN COLLECTION

Affinity API v2 auth companyMerges API

OPEN COLLECTION

Affinity API v2 auth emails API

OPEN COLLECTION

Affinity API v2 auth lists API

OPEN COLLECTION

Affinity API v2 auth meetings API

OPEN COLLECTION

Affinity API v2 auth notes API

OPEN COLLECTION

Affinity API v2 auth opportunities API

OPEN COLLECTION

Affinity API v2 auth personMerges API

OPEN COLLECTION

Affinity API v2 auth persons API

OPEN COLLECTION

Scroll for all 11

Pricing Plans 1

Published pricing tiers and plan structures.

Affinity Plans Pricing

4 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Affinity Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Affinity Finops

FINOPS

Semantic Vocabularies 1

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

Affinity Context

50 classes · 14 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Affinity API Rules

5 rules · 3 warnings 2 info

SPECTRAL

JSON Schema 14

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

Attendee

2 properties

JSON SCHEMA

CompanyData

3 properties

JSON SCHEMA

Field

5 properties

JSON SCHEMA

FieldValue

0 properties

JSON SCHEMA

Grant

3 properties

JSON SCHEMA

ListEntry

5 properties

JSON SCHEMA

Meeting

7 properties

JSON SCHEMA

notes.Note

0 properties

JSON SCHEMA

Opportunity

3 properties

JSON SCHEMA

Pagination

2 properties

JSON SCHEMA

PersonData

5 properties

JSON SCHEMA

Tenant

3 properties

JSON SCHEMA

User

4 properties

JSON SCHEMA

WhoAmI

3 properties

JSON SCHEMA

Scroll for all 14

Examples 1

Example request and response payloads for these APIs.

Affinity V2 Examples

24 fields

EXAMPLE

Security Posture 3

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

Affinity Authentication

http · 1 scheme

SECURITY

Affinity Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Affinity Trust Center

SOC 2, ISO 27001, ISO 27017, ISO 27018

SECURITY

Agentic Access 1

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

Affinity Agentic Access

46 operations · 4 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

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Vocabulary

Vocabulary

JSONLDContext

JSONLDContext

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrg

GitHubOrg

Access & Security 3

Authentication, authorization, and security posture

TrustCenter

TrustCenter

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

StatusPage

StatusPage

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 1

Properties that don't map to a standard resource type

Source (apis.yml)

name: Affinity
description: 'Affinity is a relationship intelligence CRM built for private equity, venture capital, and investment banking
  teams. It provides a REST API that enables developers to manage contacts, organizations, opportunities, lists, notes, and
  relationship timelines derived from email and calendar activity. The API is available in two versions: a legacy V1 with
  full read/write capabilities for persons, companies, opportunities, notes, interactions, reminders, and webhooks, and a
  modern V2 RESTful interface designed for internal apps, automated workflows, and third-party integrations. API access is
  included in the Scale, Advanced, and Enterprise subscription tiers, with monthly call limits ranging from 100,000 to unlimited
  depending on the plan.'
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: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/affinity.png
url: https://raw.githubusercontent.com/api-evangelist/affinity/refs/heads/main/apis.yml
created: '2026-06-12'
modified: '2026-06-12'
specificationVersion: '0.23'
type: Index
tags:
- CRM
- Relationship Intelligence
- Private Equity
- Venture Capital
- Contacts
- Organization
- Opportunities
- Deal Management
tags_raw:
- CRM
- Relationship Intelligence
- Private Equity
- Venture Capital
- Contacts
- Organizations
- Opportunities
- Deal Management
apis:
- name: Affinity API V1
  description: The legacy Affinity V1 API provides comprehensive read and write access to core CRM data including persons,
    organizations, opportunities, lists, notes, interactions, reminders, and webhooks. It uses HTTP Basic Auth or Bearer Auth
    with an API key obtained from the Affinity Settings dashboard.
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - CRM
  - Contacts
  - Organization
  - Opportunities
  - Notes
  - Webhook
  tags_raw:
  - CRM
  - Contacts
  - Organizations
  - Opportunities
  - Notes
  - Webhooks
  properties:
  - type: Documentation
    url: https://api-docs.affinity.co/
- aid: affinity:affinity-auth-api
  name: Affinity auth API
  description: Operations about auths
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - Authentication
  tags_raw:
  - auth
  properties:
  - type: OpenAPI
    url: openapi/affinity-auth-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-companies-api
  name: Affinity companies API
  description: Operations about companies
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - Companies
  tags_raw:
  - companies
  properties:
  - type: OpenAPI
    url: openapi/affinity-companies-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-companymerges-api
  name: Affinity companyMerges API
  description: Operations about company merges
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags: []
  tags_raw:
  - companyMerges
  properties:
  - type: OpenAPI
    url: openapi/affinity-companymerges-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-emails-api
  name: Affinity emails API
  description: Operations about emails
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - Emails
  tags_raw:
  - emails
  properties:
  - type: OpenAPI
    url: openapi/affinity-emails-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-lists-api
  name: Affinity lists API
  description: Operations about lists
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - List
  tags_raw:
  - lists
  properties:
  - type: OpenAPI
    url: openapi/affinity-lists-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-meetings-api
  name: Affinity meetings API
  description: Operations about meetings
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - Meetings
  tags_raw:
  - meetings
  properties:
  - type: OpenAPI
    url: openapi/affinity-meetings-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-notes-api
  name: Affinity notes API
  description: Operations about notes
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - Notes
  tags_raw:
  - notes
  properties:
  - type: OpenAPI
    url: openapi/affinity-notes-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-opportunities-api
  name: Affinity opportunities API
  description: Operations about opportunities
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - Opportunities
  tags_raw:
  - opportunities
  properties:
  - type: OpenAPI
    url: openapi/affinity-opportunities-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-personmerges-api
  name: Affinity personMerges API
  description: Operations about person merges
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags: []
  tags_raw:
  - personMerges
  properties:
  - type: OpenAPI
    url: openapi/affinity-personmerges-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
- aid: affinity:affinity-persons-api
  name: Affinity persons API
  description: Operations about persons
  humanURL: https://api-docs.affinity.co/
  baseURL: https://api.affinity.co
  tags:
  - Persons
  tags_raw:
  - persons
  properties:
  - type: OpenAPI
    url: openapi/affinity-persons-api-openapi.yml
  - type: Documentation
    url: https://developer.affinity.co/
common:
- type: AgenticAccess
  url: agentic-access/affinity-agentic-access.yml
- type: TrustCenter
  url: security/affinity-trust-center.yml
- type: DomainSecurity
  url: security/affinity-domain-security.yml
- type: Authentication
  url: authentication/affinity-authentication.yml
- type: Website
  url: https://www.affinity.co/
- type: Documentation
  url: https://developer.affinity.co/
- type: GitHubOrg
  url: https://github.com/affinity
- type: LinkedIn
  url: https://www.linkedin.com/company/project-affinity
- type: Blog
  url: https://www.affinity.co/resources/blog
- type: Pricing
  url: https://www.affinity.co/product/affinity-pricing
- type: StatusPage
  url: https://status.affinity.co/
- type: X
  url: https://x.com/affinity
- type: Plans
  url: plans/affinity-plans-pricing.yml
- type: RateLimits
  url: rate-limits/affinity-rate-limits.yml
- type: FinOps
  url: finops/affinity-finops.yml
- type: Vocabulary
  url: vocabulary/affinity-vocabulary.yml
- type: JSONLDContext
  url: json-ld/affinity-context.jsonld
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
aid: affinity

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This provider

curl "https://apis.io/api/v1/providers/affinity"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/affinity/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/affinity/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.