Inflection.io

Inflection.io is a B2B marketing automation platform positioned as a modern, AI-native replacement for legacy tools like Marketo. It unifies target accounts, product users, customers, and leads with product-usage, sales, and behavioral signals so marketing teams can build audiences, draft campaigns, map customer journeys, score accounts, and report to the CMO — executing in minutes rather than weeks. The Inflection Developer API is a JSON-over-HTTPS REST API (OpenAPI 3.1, base https://api.inflection.io/v1) for reading and writing the people in a workspace: their profiles, product and marketing activity, static lists, emails, and per-contact personalized email versions, authenticated with scoped Personal Access Tokens or an OAuth 2.1 connected app. Alongside it Inflection runs a first-party remote MCP server at mcp.inflection.io — OAuth 2.1 with PKCE, its own trust and security page — that exposes the authoring surface the REST API does not: journeys, audiences, segments, tokens and analytics, driven by specialist agents. Surfaced as a version-one-ventures portfolio company and enriched from the provider's public developer, agent, and trust surfaces.

Inflection.io publishes 6 APIs on the APIs.io network, including Contact Activity API, Contacts API, Emails API, and 3 more. Tagged areas include Company, Software-as-a-Service, Marketing, Marketing Automation, and Email Marketing.

The Inflection.io catalog on APIs.io includes 1 event-driven AsyncAPI specification.

Inflection.io’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, pricing, signup flow, and 36 more developer resources.

🌐 Visit website 📡 Source on GitHub

64.6/100 strong ▬ flat Agent 49/100 agent ready Front door AI 5/6 prominent saas Full breakdown ↓
scored 2026-09-25 · rubric v0.23.0

1 APIs 1 MCP Servers

Company Software-as-a-Service Marketing Marketing Automation Email Marketing Customer Data B2B Contacts MCP Agents Artificial Intelligence Customer Journey Webhook A2A

Kin Score

Kin Score How this is scored →
scored 2026-09-25 · rubric v0.23.0

Composite quality — 64.6/100 · strong

Contract Quality 10.8 / 19

Developer Ergonomics 9.6 / 15

Access Clarity 10.3 / 15

Operational Transparency 5.6 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 6.3 / 15

Create-or-Update Ergonomics 3.3 / 10

Agent readiness — 49/100 · agent ready

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 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 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 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 6

Agentic Commerce Well-Known Document 0 / 5

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/.

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/inflectionio: 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 6

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

Inflection.io Contact Activity API

The Contact Activity API from Inflection.io — 4 operation(s) for contact activity.

Inflection.io Contacts API

The Contacts API from Inflection.io — 6 operation(s) for contacts.

Inflection.io Emails API

The Emails API from Inflection.io — 2 operation(s) for creating and reading HTML emails.

Inflection.io Email Versions API

The Email Versions API from Inflection.io — 1 operation for pushing a per-contact personalized version of a Personalized Email Asset.

Inflection.io Lists and Members API

The Lists and Members API from Inflection.io — 7 operation(s) for lists and members.

Inflection MCP

Inflection's first-party remote MCP server — the agent-facing authoring surface for journeys, audiences, segments, emails, tokens and analytics, gated by OAuth 2.1 with PKCE.

Open Collections 4

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

API Collection

OPEN COLLECTION

Inflection Developer Contact Activity API

OPEN COLLECTION

Inflection Developer Contact Activity Contacts API

OPEN COLLECTION

Inflection Developer Contact Activity Lists and Members API

OPEN COLLECTION

MCP Servers 1

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

Inflection MCP

MCP SERVER

Pricing Plans 1

Published pricing tiers and plan structures.

Inflectionio Plans Pricing

1 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Inflectionio Rate Limits

2 limits

RATE LIMITS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Inflectionio Webhooks

ASYNCAPI

Security Posture 4

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

Inflectionio Authentication

http/oauth2 · 2 schemes

SECURITY

Inflectionio Domain Security

TLSv1.3 · DMARC

SECURITY

Inflectionio Vulnerability Disclosure

contact published

SECURITY

Inflectionio Trust Center

SOC 2, GDPR, CCPA, Penetration test

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Inflectionio Scopes

3 scopes · authorizationCode

3 scopes

SCOPES

Agentic Access 1

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

Inflectionio Agentic Access

20 operations · 10 acting

AGENTIC

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Documentation 3

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

OpenAPI

OpenAPI

Agent Surfaces 5

MCP servers, agent skills, and machine-readable catalogs

MCPServer

AgentSkill

WellKnown

LLMsTxt

AgenticAccess

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

DataModel

Lifecycle

Conformance

Webhooks

Components

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

ToolCrosswalk

ToolCrosswalk

Packages

Packages

Access & Security 7

Authentication, authorization, and security posture

Authentication

OAuthScopes

Compliance

TrustCenter

Security

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Scroll for all 7

Operate 6

Status, limits, changes, and where to get help

HelpCenter

Support

ChangeLog

ChangeLog

RateLimits

Contact

Commercial 4

Pricing, plans, and the legal terms of use

Pricing

TermsOfService

PrivacyPolicy

Plans

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

Overlay

Overlay

AgentCard

AgentCard

Source (apis.yml)

aid: inflectionio
name: Inflection.io
description: 'Inflection.io is a B2B marketing automation platform positioned as a modern, AI-native replacement for legacy
  tools like Marketo. It unifies target accounts, product users, customers, and leads with product-usage, sales, and behavioral
  signals so marketing teams can build audiences, draft campaigns, map customer journeys, score accounts, and report to the
  CMO — executing in minutes rather than weeks. The Inflection Developer API is a JSON-over-HTTPS REST API (OpenAPI 3.1, base
  https://api.inflection.io/v1) for reading and writing the people in a workspace: their profiles, product and marketing activity,
  static lists, emails, and per-contact personalized email versions, authenticated with scoped Personal Access Tokens or an
  OAuth 2.1 connected app. Alongside it Inflection runs a first-party remote MCP server at mcp.inflection.io — OAuth 2.1 with
  PKCE, its own trust and security page — that exposes the authoring surface the REST API does not: journeys, audiences, segments,
  tokens and analytics, driven by specialist agents. Surfaced as a version-one-ventures portfolio company and enriched from
  the provider''s public developer, agent, and trust surfaces.'
url: https://raw.githubusercontent.com/api-evangelist/inflectionio/refs/heads/main/apis.yml
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: usage
  onboarding: sales
  trial: false
  try_now: false
  public: false
  label: Annual contract, MMC-metered, published price ladder
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-08-13'
  method: searched
image: https://www.inflection.io/img/asset/YXNzZXRzL29nLWltYWdlLmpwZw/og-image.jpg
x-type: company
x-source: vc-portfolio
x-backed-by:
- version-one-ventures
x-tier: enriched
x-tier-reason: public-developer-api
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-08-13'
tags:
- Company
- Software-as-a-Service
- Marketing
- Marketing Automation
- Email Marketing
- Customer Data
- B2B
- Contacts
- MCP
- Agents
- Artificial Intelligence
- Customer Journey
- Webhook
- A2A
tags_raw:
- Company
- Saas
- Marketing
- Marketing Automation
- Email Marketing
- Customer Data
- B2B
- Contacts
- API
- MCP
- Agents
- Artificial Intelligence
- Customer Journeys
- Webhooks
- A2A
apis:
- aid: inflectionio:inflectionio-contact-activity-api
  name: Inflection.io Contact Activity API
  description: The Contact Activity API from Inflection.io — 4 operation(s) for contact activity.
  humanURL: https://docs.inflection.io/api-reference/introduction
  baseURL: https://api.inflection.io/v1
  tags:
  - Contact Activity
  properties:
  - type: OpenAPI
    url: openapi/inflectionio-contact-activity-api-openapi.yml
  - type: Documentation
    url: https://docs.inflection.io/api-reference/introduction
  - type: APIReference
    url: https://docs.inflection.io/api-reference/contact-activity/get-product-activity
- aid: inflectionio:inflectionio-contacts-api
  name: Inflection.io Contacts API
  description: The Contacts API from Inflection.io — 6 operation(s) for contacts.
  humanURL: https://docs.inflection.io/api-reference/introduction
  baseURL: https://api.inflection.io/v1
  tags:
  - Contacts
  properties:
  - type: OpenAPI
    url: openapi/inflectionio-contacts-api-openapi.yml
  - type: Documentation
    url: https://docs.inflection.io/api-reference/introduction
  - type: APIReference
    url: https://docs.inflection.io/api-reference/contacts/get-contact-by-id
- aid: inflectionio:inflectionio-emails-api
  name: Inflection.io Emails API
  description: The Emails API from Inflection.io — 2 operation(s) for creating and reading HTML emails.
  humanURL: https://docs.inflection.io/api-reference/introduction
  baseURL: https://api.inflection.io/v1
  tags:
  - Email
  tags_raw:
  - Emails
  properties:
  - type: OpenAPI
    url: openapi/inflectionio-emails-api-openapi.yml
  - type: Documentation
    url: https://docs.inflection.io/api-reference/introduction
  - type: APIReference
    url: https://docs.inflection.io/api-reference/emails/create-an-email
- aid: inflectionio:inflectionio-email-versions-api
  name: Inflection.io Email Versions API
  description: The Email Versions API from Inflection.io — 1 operation for pushing a per-contact personalized version of a
    Personalized Email Asset.
  humanURL: https://docs.inflection.io/api-reference/introduction
  baseURL: https://api.inflection.io/v1
  tags:
  - Email Versions
  properties:
  - type: OpenAPI
    url: openapi/inflectionio-email-versions-api-openapi.yml
  - type: Documentation
    url: https://docs.inflection.io/agents/personalized-email
  - type: APIReference
    url: https://docs.inflection.io/api-reference/email-versions/set-a-personalized-email-version
- aid: inflectionio:inflectionio-lists-and-members-api
  name: Inflection.io Lists and Members API
  description: The Lists and Members API from Inflection.io — 7 operation(s) for lists and members.
  humanURL: https://docs.inflection.io/api-reference/introduction
  baseURL: https://api.inflection.io/v1
  tags:
  - Lists and Members
  properties:
  - type: OpenAPI
    url: openapi/inflectionio-lists-and-members-api-openapi.yml
  - type: Documentation
    url: https://docs.inflection.io/api-reference/introduction
  - type: APIReference
    url: https://docs.inflection.io/api-reference/lists-and-members/create-a-list
- aid: inflectionio:inflectionio-mcp
  name: Inflection MCP
  description: Inflection's first-party remote MCP server — the agent-facing authoring surface for journeys, audiences, segments,
    emails, tokens and analytics, gated by OAuth 2.1 with PKCE.
  humanURL: https://docs.inflection.io/agents/inflection-mcp
  baseURL: https://mcp.inflection.io/
  tags:
  - MCP
  - Agents
  properties:
  - type: MCPServer
    url: mcp/inflectionio-mcp.yml
  - type: ToolCrosswalk
    url: mcp/inflectionio-tool-crosswalk.yml
  - type: Documentation
    url: https://docs.inflection.io/agents/inflection-mcp
  - type: Authentication
    url: https://docs.inflection.io/agents/connected-apps-oauth
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://www.inflection.io
- type: DeveloperPortal
  url: https://docs.inflection.io/api-reference/introduction
- type: Documentation
  url: https://docs.inflection.io/api-reference/introduction
- type: APIReference
  url: https://docs.inflection.io/api-reference/introduction
- type: GettingStarted
  url: https://docs.inflection.io/api-reference/quickstart
- type: HelpCenter
  url: https://docs.inflection.io
- type: Support
  url: https://docs.inflection.io
- type: Blog
  url: https://www.inflection.io/blog
- type: Pricing
  url: https://www.inflection.io/pricing
- type: SignUp
  url: https://app.inflection.io/login/start
- type: Login
  url: https://app.inflection.io/login/start
- type: TermsOfService
  url: https://www.inflection.io/legal/terms
- type: PrivacyPolicy
  url: https://www.inflection.io/legal/privacy-policy
- type: GitHubOrganization
  url: https://github.com/inflectionio
- type: ChangeLog
  url: https://docs.inflection.io/whats-new/july-2026
- type: ChangeLog
  url: changelog/inflectionio-changelog.yml
- type: OpenAPI
  url: openapi/_original/inflectionio-openapi-original.yml
- type: Overlay
  url: overlays/inflectionio-openapi-overlay.yaml
- type: Authentication
  url: authentication/inflectionio-authentication.yml
- type: OAuthScopes
  url: scopes/inflectionio-scopes.yml
- type: Conventions
  url: conventions/inflectionio-conventions.yml
- type: ErrorCatalog
  url: errors/inflectionio-problem-types.yml
- type: DataModel
  url: data-model/inflectionio-data-model.yml
- type: Lifecycle
  url: lifecycle/inflectionio-lifecycle.yml
- type: Conformance
  url: conformance/inflectionio-conformance.yml
- type: Compliance
  url: https://docs.inflection.io/agents/mcp-trust-security
- type: TrustCenter
  url: security/inflectionio-trust-center.yml
- type: Security
  url: https://docs.inflection.io/agents/mcp-trust-security
- type: VulnerabilityDisclosure
  url: security/inflectionio-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/inflectionio-domain-security.yml
- type: MCPServer
  url: mcp/inflectionio-mcp.yml
- type: ToolCrosswalk
  url: mcp/inflectionio-tool-crosswalk.yml
- type: AgentCard
  url: a2a/inflectionio-a2a.yml
- type: AgentSkill
  url: skills/_index.yml
- type: WellKnown
  url: well-known/inflectionio-well-known.yml
- type: LLMsTxt
  url: llms/inflectionio-llms.txt
- type: AgenticAccess
  url: agentic-access/inflectionio-agentic-access.yml
- type: RateLimits
  url: rate-limits/inflectionio-rate-limits.yml
- type: Plans
  url: plans/inflectionio-plans-pricing.yml
- type: Webhooks
  url: asyncapi/inflectionio-webhooks.yml
- type: Packages
  url: packages/inflectionio-packages.yml
- type: Components
  url: components/inflectionio-components.yml
- type: Contact
  url: mailto:support@inflection.io
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 18
  pass: local-v1

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