Affirm

Affirm is a buy-now-pay-later platform offering installment loans at point-of-sale via merchant SDKs and direct APIs. Public Series A through F-funded company.

Affirm publishes 9 APIs on the APIs.io network, including Transactions API, Authorization API, Cards API, and 6 more. Tagged areas include Fintech, BNPL, Lending, Payments, and Consumer.

The Affirm catalog on APIs.io includes 1 event-driven AsyncAPI specification, 6 JSON-LD contexts, and 3 Spectral governance rulesets.

Affirm’s developer surface includes documentation, changelog, authentication, and 10 more developer resources.

🌐 Visit website 📡 Source on GitHub

37.3/100 thin ▬ flat Agent 28/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

5 APIs

Fintech BNPL Lending Payments Consumer

Kin Score

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

Composite quality — 37.3/100 · thin

Contract Quality 14.5 / 19

Developer Ergonomics 3.2 / 15

Access Clarity 3.2 / 15

Operational Transparency 0.8 / 10

Contract Governance 1.2 / 9

Discoverability 5.4 / 8

Regulatory Posture 5.2 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 28/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 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 6 / 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

Regulatory Posture applies to this provider. Its tags matched the Payments 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/affirm: 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.

Affirm Checkout API

Initialize and authorize Affirm checkout flows for online merchants.

Affirm Charges API

Capture, void, and refund Affirm charges; read transaction details.

Affirm Transactions API

Read transactions, settlements, and disputes.

Affirm Authorization API

Server-side operations for authorizing Affirm transactions after a customer completes the checkout flow and a checkout token is returned.

Affirm Cards API

Operations for managing virtual card numbers (VCN) issued via the Affirm Lite integration pattern.

Affirm Checkouts API

Operations for creating, retrieving, updating, and resending Affirm checkout sessions.

Affirm Disputes API

Operations for listing, retrieving, contesting, and closing payment disputes initiated by customers.

Affirm Promos API

Operations for retrieving dynamic promotional messaging and financing term information to display on merchant web pages.

Affirm Settlement Events API

Operations for listing settlement events and summaries that track disbursement activity.

Affirm Transaction Events API

Operations for listing transaction event records associated with transaction lifecycle changes.

Affirm Transactions API

Post-authorization transaction management operations including capture, void, and refund.

Scroll for all 11

Open Collections 14

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

API Collection

OPEN COLLECTION

Affirm Checkout Authorization API

OPEN COLLECTION

Affirm Checkout Authorization Cards API

OPEN COLLECTION

Affirm Checkout API

OPEN COLLECTION

Affirm Checkout Authorization Checkouts API

OPEN COLLECTION

Affirm Direct API

OPEN COLLECTION

Affirm Checkout Authorization Disputes API

OPEN COLLECTION

Affirm Disputes API

OPEN COLLECTION

Affirm Checkout Authorization Promos API

OPEN COLLECTION

Affirm Promos API

OPEN COLLECTION

Affirm Checkout Authorization Settlement Events API

OPEN COLLECTION

Affirm Checkout Authorization Transaction Events API

OPEN COLLECTION

Affirm Checkout Authorization Transactions API

OPEN COLLECTION

Affirm Transactions API

OPEN COLLECTION

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GraphQL 1

GraphQL schemas published by this provider.

Affirm GraphQL Schema

This document describes the conceptual GraphQL schema for the Affirm Buy Now Pay Later (BNPL) platform. Affirm's production API is REST-based; this schema models the same domain...

GRAPHQL

Pricing Plans 1

Published pricing tiers and plan structures.

Affirm Plans Pricing

1 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Affirm Rate Limits

1 limits

RATE LIMITS

FinOps 1

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

Affirm Finops

FINOPS

Event Specifications 1

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

Affirm Webhooks

Affirm uses webhooks to notify merchant endpoints in real time when events occur during the customer checkout and prequalification flows. Webhooks are available to Key and Enter...

ASYNCAPI

Semantic Vocabularies 6

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

Affirm Checkout Context

11 classes · 50 properties

JSON-LD

Affirm Context

0 classes · 9 properties

JSON-LD

Affirm Direct Context

3 classes · 23 properties

JSON-LD

Affirm Disputes Context

3 classes · 21 properties

JSON-LD

Affirm Promos Context

6 classes · 30 properties

JSON-LD

Affirm Transactions Context

4 classes · 22 properties

JSON-LD

Spectral Rules 3

Spectral governance rulesets for linting and validating these APIs.

Affirm API Rules

8 rules · 1 errors 7 warnings

SPECTRAL

Affirm API Rules

6 rules · 5 warnings 1 info

SPECTRAL

Affirm API Rules

42 rules · 16 errors 24 warnings 2 info

SPECTRAL

JSON Schema 27

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

Affirm Checkout

22 properties

JSON SCHEMA

Affirm Dispute

12 properties

JSON SCHEMA

Affirm Transaction

13 properties

JSON SCHEMA

AddressObject

6 properties

JSON SCHEMA

CheckoutRequest

15 properties

JSON SCHEMA

Checkout

18 properties

JSON SCHEMA

ContactObject

4 properties

JSON SCHEMA

DiscountObject

2 properties

JSON SCHEMA

ItemObject

7 properties

JSON SCHEMA

MerchantObject

5 properties

JSON SCHEMA

NameObject

3 properties

JSON SCHEMA

StoreObject

2 properties

JSON SCHEMA

Card

10 properties

JSON SCHEMA

FileObject

6 properties

JSON SCHEMA

Transaction

9 properties

JSON SCHEMA

Dispute

12 properties

JSON SCHEMA

EvidenceItem

4 properties

JSON SCHEMA

EvidenceRequest

6 properties

JSON SCHEMA

FinancingTerm

7 properties

JSON SCHEMA

OfferContent

3 properties

JSON SCHEMA

PromoConfig

7 properties

JSON SCHEMA

PromoContent

8 properties

JSON SCHEMA

PromoResponse

2 properties

JSON SCHEMA

SettlementEvent

7 properties

JSON SCHEMA

SettlementEventSummary

5 properties

JSON SCHEMA

TransactionEvent

8 properties

JSON SCHEMA

Transaction

13 properties

JSON SCHEMA

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JSON Structure 27

JSON Structure definitions describing this provider's data shapes.

Affirm Checkout Structure

22 properties

JSON STRUCTURE

Affirm Dispute Structure

12 properties

JSON STRUCTURE

Affirm Transaction Structure

13 properties

JSON STRUCTURE

Checkout Address Object Structure

6 properties

JSON STRUCTURE

Checkout Checkout Request Structure

15 properties

JSON STRUCTURE

Checkout Checkout Structure

18 properties

JSON STRUCTURE

Checkout Contact Object Structure

4 properties

JSON STRUCTURE

Checkout Discount Object Structure

2 properties

JSON STRUCTURE

Checkout Item Object Structure

7 properties

JSON STRUCTURE

Checkout Merchant Object Structure

5 properties

JSON STRUCTURE

Checkout Name Object Structure

3 properties

JSON STRUCTURE

Checkout Store Object Structure

2 properties

JSON STRUCTURE

Direct Api Card Structure

10 properties

JSON STRUCTURE

Direct Api File Object Structure

6 properties

JSON STRUCTURE

Direct Api Transaction Structure

9 properties

JSON STRUCTURE

Disputes Dispute Structure

12 properties

JSON STRUCTURE

Disputes Evidence Item Structure

4 properties

JSON STRUCTURE

Disputes Evidence Request Structure

6 properties

JSON STRUCTURE

Promos Financing Term Structure

7 properties

JSON STRUCTURE

Promos Offer Content Structure

3 properties

JSON STRUCTURE

Promos Promo Config Structure

7 properties

JSON STRUCTURE

Promos Promo Content Structure

8 properties

JSON STRUCTURE

Promos Promo Response Structure

2 properties

JSON STRUCTURE

Transactions Settlement Event Structure

7 properties

JSON STRUCTURE

Transactions Settlement Event Summary Structure

5 properties

JSON STRUCTURE

Transactions Transaction Event Structure

8 properties

JSON STRUCTURE

Transactions Transaction Structure

13 properties

JSON STRUCTURE

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Examples 27

Example request and response payloads for these APIs.

Affirm Checkout Example

22 fields

EXAMPLE

Affirm Dispute Example

12 fields

EXAMPLE

Affirm Transaction Example

13 fields

EXAMPLE

Checkout Address Object Example

6 fields

EXAMPLE

Checkout Checkout Example

18 fields

EXAMPLE

Checkout Checkout Request Example

15 fields

EXAMPLE

Checkout Contact Object Example

4 fields

EXAMPLE

Checkout Discount Object Example

2 fields

EXAMPLE

Checkout Item Object Example

7 fields

EXAMPLE

Checkout Merchant Object Example

5 fields

EXAMPLE

Checkout Name Object Example

3 fields

EXAMPLE

Checkout Store Object Example

2 fields

EXAMPLE

Direct Api Card Example

10 fields

EXAMPLE

Direct Api File Object Example

6 fields

EXAMPLE

Direct Api Transaction Example

9 fields

EXAMPLE

Disputes Dispute Example

12 fields

EXAMPLE

Disputes Evidence Item Example

4 fields

EXAMPLE

Disputes Evidence Request Example

6 fields

EXAMPLE

Promos Financing Term Example

7 fields

EXAMPLE

Promos Offer Content Example

3 fields

EXAMPLE

Promos Promo Config Example

7 fields

EXAMPLE

Promos Promo Content Example

8 fields

EXAMPLE

Promos Promo Response Example

2 fields

EXAMPLE

Transactions Settlement Event Example

7 fields

EXAMPLE

Transactions Settlement Event Summary Example

5 fields

EXAMPLE

Transactions Transaction Event Example

8 fields

EXAMPLE

Transactions Transaction Example

13 fields

EXAMPLE

Scroll for all 27

Security Posture 3

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

Affirm Authentication

http · 1 scheme

SECURITY

Affirm Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Affirm Trust Center

SOC 2, PCI DSS

SECURITY

Agentic Access 1

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

Affirm Agentic Access

29 operations · 18 acting

AGENTIC

Resources

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

LlmsText

LlmsText

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 3

Authentication, authorization, and security posture

TrustCenter

TrustCenter

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

ChangeLog

ChangeLog

RateLimits

RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

Plans

Plans

FinOps

FinOps

Company 2

The organization behind the API

LinkedIn

Website

Website

Source (apis.yml)

aid: affirm
url: https://raw.githubusercontent.com/api-evangelist/affirm/refs/heads/main/apis.yml
name: Affirm
kind: company
description: Affirm is a buy-now-pay-later platform offering installment loans at point-of-sale via merchant SDKs and direct
  APIs. Public Series A through F-funded company.
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: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - plans
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/affirm.png
tags:
- Fintech
- BNPL
- Lending
- Payments
- Consumer
created: '2026-05-08'
modified: '2026-05-08'
specificationVersion: '0.23'
apis:
- name: Affirm Checkout API
  description: Initialize and authorize Affirm checkout flows for online merchants.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Checkout
  - BNPL
  properties:
  - type: Documentation
    url: https://docs.affirm.com/developers
  - url: graphql/affirm-graphql.md
    type: GraphQL
- name: Affirm Charges API
  description: Capture, void, and refund Affirm charges; read transaction details.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Charges
  - Payments
  properties:
  - type: Documentation
    url: https://docs.affirm.com/developers
- name: Affirm Transactions API
  description: Read transactions, settlements, and disputes.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Transaction
  - Settlement
  tags_raw:
  - Transactions
  - Settlements
  properties:
  - type: Documentation
    url: https://docs.affirm.com/developers
- aid: affirm:affirm-authorization-api
  name: Affirm Authorization API
  description: Server-side operations for authorizing Affirm transactions after a customer completes the checkout flow and
    a checkout token is returned.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Authorization
  properties:
  - type: OpenAPI
    url: openapi/affirm-authorization-api-openapi.yml
- aid: affirm:affirm-cards-api
  name: Affirm Cards API
  description: Operations for managing virtual card numbers (VCN) issued via the Affirm Lite integration pattern.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Cards
  properties:
  - type: OpenAPI
    url: openapi/affirm-cards-api-openapi.yml
- aid: affirm:affirm-checkouts-api
  name: Affirm Checkouts API
  description: Operations for creating, retrieving, updating, and resending Affirm checkout sessions.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Checkouts
  properties:
  - type: OpenAPI
    url: openapi/affirm-checkouts-api-openapi.yml
- aid: affirm:affirm-disputes-api
  name: Affirm Disputes API
  description: Operations for listing, retrieving, contesting, and closing payment disputes initiated by customers.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Disputes
  properties:
  - type: OpenAPI
    url: openapi/affirm-disputes-api-openapi.yml
- aid: affirm:affirm-promos-api
  name: Affirm Promos API
  description: Operations for retrieving dynamic promotional messaging and financing term information to display on merchant
    web pages.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Promos
  properties:
  - type: OpenAPI
    url: openapi/affirm-promos-api-openapi.yml
- aid: affirm:affirm-settlement-events-api
  name: Affirm Settlement Events API
  description: Operations for listing settlement events and summaries that track disbursement activity.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Settlement Events
  properties:
  - type: OpenAPI
    url: openapi/affirm-settlement-events-api-openapi.yml
- aid: affirm:affirm-transaction-events-api
  name: Affirm Transaction Events API
  description: Operations for listing transaction event records associated with transaction lifecycle changes.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Transaction Events
  properties:
  - type: OpenAPI
    url: openapi/affirm-transaction-events-api-openapi.yml
- aid: affirm:affirm-transactions-api
  name: Affirm Transactions API
  description: Post-authorization transaction management operations including capture, void, and refund.
  humanURL: https://docs.affirm.com/developers
  baseURL: https://api.affirm.com
  tags:
  - Transaction
  tags_raw:
  - Transactions
  properties:
  - type: OpenAPI
    url: openapi/affirm-transactions-api-openapi.yml
common:
- type: Documentation
  url: https://www.affirm.com/docs
- type: ChangeLog
  url: https://docs.affirm.com/affirm-developers/changelog
- type: AgenticAccess
  url: agentic-access/affirm-agentic-access.yml
- type: TrustCenter
  url: security/affirm-trust-center.yml
- type: DomainSecurity
  url: security/affirm-domain-security.yml
- type: Authentication
  url: authentication/affirm-authentication.yml
- type: GitHubOrganization
  url: https://github.com/Affirm
- type: LinkedIn
  url: https://www.linkedin.com/company/affirm
- type: Website
  url: https://www.affirm.com/
- type: Plans
  url: plans/affirm-plans-pricing.yml
- type: RateLimits
  url: rate-limits/affirm-rate-limits.yml
- type: FinOps
  url: finops/affirm-finops.yml
- type: LlmsText
  url: https://docs.affirm.com/llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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