Chain

Chain is a stablecoin payments infrastructure platform that lets enterprises move money globally across both traditional banking rails and digital-currency networks. Its unified REST API covers funding, payouts and payees; virtual and physical card issuing; wallet registration with compliance screening; and a double-entry ledger for reconciliation. Chain connects ACH, Fedwire, FedNow, SEPA, Faster Payments, Visa and Mastercard with multi-stablecoin support (USDC, USDT, USDP, RLUSD) for real-time settlement and payouts to 200+ countries. The platform exposes API-key (Bearer) authentication, an idempotency-key header, webhooks with signature verification, and separate sandbox and live environments for developers.

Chain is listed with 1 API on the APIs.io network. Tagged areas include Company, Payments, Stablecoins, Cryptocurrency, and Blockchain.

Chain’s developer surface includes documentation, API reference, getting-started guide, authentication, sandbox, engineering blog, support, and 16 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

33.3/100 thin ▬ flat Agent 10/100 agent aware Front door AI 1/6 silent saas Full breakdown ↓
scored 2026-10-31 · rubric v0.25.0 · Show this score on your site →

1 API

Company Payments Stablecoins Cryptocurrency Blockchain Financial Services Wallets Cards Cross-Border Payments

Kin Score

Kin Score How this is scored →
scored 2026-10-31 · rubric v0.25.0

Composite quality — 33.3/100 · thin

Contract Quality 0.0 / 21

Developer Ergonomics 12.1 / 17

Access Clarity 5.8 / 17

Operational Transparency 4.9 / 11

Contract Governance 0.0 / 10

Discoverability 5.6 / 9

Regulatory Posture 2.7 / 15

Agent readiness — 10/100 · 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 9 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 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

Pagination 5 / 5

Distinct Operations 3 / 3

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 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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<a href="https://apis.io/providers/chain/"><img src="https://apis.io/badge/chain/card.svg" alt="Chain on APIs.io — Kin Score by API Evangelist"></a>

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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
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)

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 34.2 — up to +13.2 composite points
Contract Governance scores 0.0 — up to +12.0 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/chain/apis.yml: open an issue on github.com/api-evangelist/chain 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
Stablecoins and Tokenization (stablecoin issuers, tokenized assets)	distribution	9.6 (thin)	-	1

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.

APIs 1

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

Chain API

Chain's unified REST API for stablecoin payments (funding, payouts, payees), card issuing, wallets, and a double-entry ledger. Bearer API-key auth with sandbox and live key pref...

Security Posture 2

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

Chain Authentication

apiKey · 1 scheme

SECURITY

Chain Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

GettingStarted

Sandbox

SignUp

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 4

Pagination, idempotency, versioning, errors, and events

Webhooks

Conventions

Idempotency

Lifecycle

Build 3

SDKs, sample code, and the tooling you integrate with

SDKs

SDKs

Packages

Packages

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 3

Status, limits, changes, and where to get help

Support

Support

ChangeLog

ChangeLog

StatusPage

StatusPage

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: chain
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:
  - authentication
  - security
  - sandbox
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/chain.png
name: Chain
description: Chain is a stablecoin payments infrastructure platform that lets enterprises move money globally across both
  traditional banking rails and digital-currency networks. Its unified REST API covers funding, payouts and payees; virtual
  and physical card issuing; wallet registration with compliance screening; and a double-entry ledger for reconciliation.
  Chain connects ACH, Fedwire, FedNow, SEPA, Faster Payments, Visa and Mastercard with multi-stablecoin support (USDC, USDT,
  USDP, RLUSD) for real-time settlement and payouts to 200+ countries. The platform exposes API-key (Bearer) authentication,
  an idempotency-key header, webhooks with signature verification, and separate sandbox and live environments for developers.
url: https://raw.githubusercontent.com/api-evangelist/chain/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- 500-global
- pantera-capital
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-18'
tags:
- Company
- Payments
- Stablecoins
- Cryptocurrency
- Blockchain
- Financial Services
- Wallets
- Cards
- Cross-Border Payments
tags_raw:
- Company
- Payments
- Stablecoin
- Cryptocurrency
- Blockchain
- Financial Services
- Wallets
- Cards
- Cross-Border Payments
- API
- Financial-Services
apis:
- name: Chain API
  description: Chain's unified REST API for stablecoin payments (funding, payouts, payees), card issuing, wallets, and a double-entry
    ledger. Bearer API-key auth with sandbox and live key prefixes (sk_sandbox_ / sk_live_) and an X-Idempotency-Key header
    for safe retries.
  humanURL: https://chain.com/documentation
  baseURL: https://api.chain.com/v1
  properties:
  - type: Documentation
    url: https://chain.com/documentation
  - type: Authentication
    url: https://chain.com/documentation/authentication
  - type: Webhooks
    url: https://chain.com/documentation/webhooks
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: DomainSecurity
  url: security/chain-domain-security.yml
- type: Website
  url: https://chain.com
- type: DeveloperPortal
  url: https://chain.com/documentation
- type: Documentation
  url: https://chain.com/documentation
- type: APIReference
  url: https://chain.com/documentation
- type: GettingStarted
  url: https://chain.com/documentation
- type: Authentication
  url: authentication/chain-authentication.yml
- type: Webhooks
  url: https://chain.com/documentation/webhooks
- type: SDKs
  url: https://chain.com/documentation/sdks
- type: Packages
  url: packages/chain-packages.yml
- type: Conventions
  url: conventions/chain-conventions.yml
- type: Idempotency
  url: conventions/chain-conventions.yml
- type: Lifecycle
  url: lifecycle/chain-lifecycle.yml
- type: Sandbox
  url: sandbox/chain-sandbox.yml
- type: LLMsTxt
  url: llms/chain-llms.txt
- type: Blog
  url: https://chain.com/blog
- type: Support
  url: https://chain.com/support
- type: ChangeLog
  url: https://chain.com/developers/changelog
- type: StatusPage
  url: https://chain.com/developers/status
- type: GitHubOrganization
  url: https://github.com/chain
- type: SignUp
  url: https://app.chain.com
- type: TermsOfService
  url: https://chain.com/terms
- type: PrivacyPolicy
  url: https://chain.com/privacy-policy
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

Chain API — frequently asked questions

Does Chain have an API?

Yes. APIs.io lists 1 API from Chain, including Chain API.

How do I authenticate with the Chain API?

Chain uses bearer-token authentication (apiKey · 1 scheme). The details are profiled on APIs.io as Chain Authentication.

Is the Chain API ready for AI agents?

Chain has a Kin Score of 33.3 out of 100 (thin) and an Agent Readiness score of 9.6 (agent-aware), scored by API Evangelist on 2026-10-31.

Work with this as data

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

MCP server

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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.

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