Circle

Circle Internet Financial is the issuer of USDC and EURC and operates a developer platform for moving regulated stablecoin money across the internet. Their APIs cover programmable wallets (developer- and user-controlled), gas sponsorship, the Cross-Chain Transfer Protocol (CCTP), Gateway unified balances, the Smart Contract Platform, the Circle Payments Network (CPN) for cross-border payments, compliance, StableFX trading on Arc, and xReserve for issuing USDC-backed stablecoins.

Circle publishes 2 API contracts indexed on the APIs.io network, including Audit Logs API, and 1 more. Tagged areas include Blockchain, Compliance, Cross-Chain, Currency, and Money.

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

Circle’s developer surface includes API reference, authentication, developer portal, developer console, getting-started guide, support, engineering blog, and 22 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

41.1/100 developing ▬ flat Agent 48/100 agent ready Front door AI 4/6 moderate Heartbeat 100/100 alive saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract 2 MCP Servers

Blockchain Compliance Cross-Chain Currency Money Payments Stablecoins Transfers USDC Wallets Stablecoin Issuance

Kin Score

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

Composite quality — 41.1/100 · developing

Contract Quality 13.1 / 21

Developer Ergonomics 8.2 / 17

Access Clarity 3.1 / 17

Operational Transparency 2.9 / 11

Contract Governance 1.4 / 10

Discoverability 6.4 / 9

Regulatory Posture 2.8 / 15

Agent readiness — 48/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 0 / 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 4 / 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 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 does not apply to this provider. The published contracts declare no write operations, and a read-only API cannot create-or-update. The facet is excluded from this provider's denominator entirely — not scored zero. A reference or data API is not deficient for being unable to upsert.

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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Agent readiness — checks not met, largest first (exact, from this profile):

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
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)
Protected Resource Metadata +5 pts — a served /.well-known/oauth-protected-resource carrying `resource` (documented), and naming its authorization_servers (verified)
Agentic Commerce Well-Known Document +5 pts — a parsing /.well-known/ucp.json or acp.json declaring a version and at least one service, OR (0.27) a live x402 payment challenge from _data/x402-adoption.json — `self` when its endpoints are on the provider's own domain, `platform` when they are on a vendor's

2 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 18.4 — up to +16.3 composite points
Developer Ergonomics scores 48.1 — up to +10.4 composite points
Contract Governance scores 13.6 — up to +10.4 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/circle/apis.yml: open an issue on github.com/api-evangelist/circle 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
Crypto and Digital-Asset Exchanges	regulated	56.0	-	1
Agent Skills (SKILL.md packages)	regulated	56.0	-	1
Stablecoins and Tokenization (stablecoin issuers, tokenized assets)	regulated	56.0	-	1
x402 Micropayments & Agentic Pay-per-Call	regulated	56.0	-	1
France Authorised Financial Firms (ACPR REGAFI + AMF white list)	regulated	56.0	-	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.

Standards implemented 2

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.

Model Context Protocol (MCP)

measured — observed by APIs.io (verified)

OpenAPI

measured — observed by APIs.io (published)

APIs 2

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

Gas Station and Paymaster

Sponsor gas fees on behalf of users or let users pay gas in USDC via Circle Paymaster, removing native-token friction from onboarding.

Circle Audit Logs API

Retrieve a log of actions taken in your Circle account.

Open Collections 7

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

Circle Web3 Services (W3S) — Developer-Controlled Wallets NFTs API

OPEN COLLECTION

Circle Web3 Services (W3S) — Developer-Controlled Wallets NFTs Signing API

OPEN COLLECTION

Circle Web3 Services (W3S) — Developer-Controlled Wallets NFTs Tokens API

OPEN COLLECTION

Circle Web3 Services (W3S) — Developer-Controlled Wallets NFTs Transactions API

OPEN COLLECTION

Circle Web3 Services (W3S) — Developer-Controlled Wallets NFTs Wallet Sets API

OPEN COLLECTION

Circle Web3 Services (W3S) — Developer-Controlled NFTs Wallets API

OPEN COLLECTION

Circle Web3 Services (W3S) — Developer-Controlled Wallets API

OPEN COLLECTION

Scroll for all 7

MCP Servers 2

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

Circle MCP Server

MCP SERVER

Circle MCP Server

Remote MCP server at api.circle.com over HTTP; 4 tools listed.

MCP SERVER

Circle API pricing

Not yet checked against Circle's own pricing page. Compiled by API Evangelist on 2026-05-04; confirm before you rely on a figure. A free plan or tier is listed.

Plan	Price
Free freemium	Free
Professional paid	Free
Enterprise enterprise	—

Plan details, limits and sources →

Rate limits

Free Tier Default: 10 requests per minute
Free Tier Monthly Quota: 1000 requests per month
Professional Tier Default: 100 requests per minute

Compiled by API Evangelist, not yet checked against Circle's documentation. All 5 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

Circle Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Circle Rate Limits

5 limits

RATE LIMITS

Service Levels 1

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

Circle

SLA

FinOps 1

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

Circle Finops

FINOPS

Event Specifications 1

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

Circle Webhook Notifications

AsyncAPI description of Circle's outbound webhook (notification) surfaces. Circle delivers event notifications by POSTing a JSON body to a subscriber endpoint that is registered...

ASYNCAPI

Semantic Vocabularies 1

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

Circle Context

0 classes · 6 properties

JSON-LD

Spectral Rules 3

Spectral governance rulesets for linting and validating these APIs.

Circle — asyncapi rules

8 rules · 1 errors 7 warnings

SPECTRAL

Circle — jsonschema rules

5 rules · 3 warnings 2 info

SPECTRAL

Circle API Rules

9 rules · 4 errors 4 warnings 1 info

SPECTRAL

JSON Schema 2

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

Circle Transaction

17 properties

JSON SCHEMA

Circle Wallet

11 properties

JSON SCHEMA

Security Posture 2

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

Circle Authentication

http · 1 scheme

SECURITY

Circle Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Agentic Access 1

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

Circle Agentic Access

30 operations · 18 acting · 3 human-in-the-loop

30 operations · 18 acting

AGENTIC

Resources

Get Started 3

Portal, sign-up, and the first successful call

Portal

Portal

Console

Console

GettingStarted

GettingStarted

Documentation 4

Reference material describing how the API behaves

APIReference

JSONSchema

JSONSchema

AsyncAPI

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

AgentSkills

MCPServer

AgenticAccess

LlmsText

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

JSONLD

JSONLD

Spectral

Spectral

Build 2

SDKs, sample code, and the tooling you integrate with

PostmanWorkspace

PostmanWorkspace

GitHubOrganization

GitHubOrganization

Access & Security 3

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Authentication

Authentication

Operate 4

Status, limits, changes, and where to get help

RateLimits

StatusPage

Support

Community

Commercial 4

Pricing, plans, and the legal terms of use

Plans

FinOps

PrivacyPolicy

TermsOfService

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Source (apis.yml)

aid: circle
name: Circle
url: https://raw.githubusercontent.com/api-evangelist/circle/refs/heads/main/apis.yml
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-09-21
tags:
- Blockchain
- Compliance
- Cross-Chain
- Currency
- Money
- Payments
- Stablecoins
- Transfers
- USDC
- Wallets
- Stablecoin Issuance
tags_raw:
- Blockchain
- Compliance
- Cross-Chain
- Currency
- Money
- Payments
- Stablecoin
- Transfers
- USDC
- Wallets
- Stablecoin Issuance
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: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/circle.png
access: 3rd-Party
created: '2024-11-07'
modified: '2026-05-30'
position: Consuming
specificationVersion: '0.23'
description: Circle Internet Financial is the issuer of USDC and EURC and operates a developer platform for moving regulated
  stablecoin money across the internet. Their APIs cover programmable wallets (developer- and user-controlled), gas sponsorship,
  the Cross-Chain Transfer Protocol (CCTP), Gateway unified balances, the Smart Contract Platform, the Circle Payments Network
  (CPN) for cross-border payments, compliance, StableFX trading on Arc, and xReserve for issuing USDC-backed stablecoins.
apis:
- aid: circle:gas-station
  name: Gas Station and Paymaster
  tags:
  - Gas Sponsorship
  - Paymaster
  - USDC
  humanURL: https://developers.circle.com/w3s/gas-station
  baseURL: https://api.circle.com/v1/w3s
  properties:
  - url: https://developers.circle.com/w3s/gas-station
    type: Documentation
  description: Sponsor gas fees on behalf of users or let users pay gas in USDC via Circle Paymaster, removing native-token
    friction from onboarding.
- aid: circle:circle-audit-logs-api
  name: Circle Audit Logs API
  description: Retrieve a log of actions taken in your Circle account.
  humanURL: https://developers.circle.com/w3s/gas-station
  baseURL: https://api.circle.com/v1/w3s
  tags:
  - Audit Logs
  properties:
  - type: OpenAPI
    url: openapi/circle-audit-logs-api-openapi.yml
  - type: Documentation
    url: https://developers.circle.com/w3s/programmable-wallets
  - type: Documentation
    url: https://developers.circle.com/w3s/user-controlled-wallets
  - type: Documentation
    url: https://developers.circle.com/cctp
  - type: Documentation
    url: https://developers.circle.com/gateway
  - type: Documentation
    url: https://developers.circle.com/w3s/smart-contract-platform
  - type: Documentation
    url: https://developers.circle.com/cpn
  - type: Documentation
    url: https://developers.circle.com/w3s/compliance-engine
  - type: Documentation
    url: https://developers.circle.com/stablefx
  - type: Documentation
    url: https://developers.circle.com/xreserve
common:
- type: PostmanWorkspace
  url: https://www.postman.com/kinlaneapi/circle/overview
- type: Plans
  url: plans/circle-plans-pricing.yml
- type: RateLimits
  url: rate-limits/circle-rate-limits.yml
- type: FinOps
  url: finops/circle-finops.yml
- type: AgentSkills
  url: https://developers.circle.com/ai/skills
- type: APIReference
  url: https://developers.circle.com/api-reference
- type: MCPServer
  url: https://developers.circle.com/ai/mcp
- type: AgenticAccess
  url: agentic-access/circle-agentic-access.yml
- type: DomainSecurity
  url: security/circle-domain-security.yml
- type: Authentication
  url: authentication/circle-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/circleco
- type: Website
  url: https://www.circle.com/
- type: Portal
  url: https://developers.circle.com/
- type: Console
  url: https://console.circle.com/
- type: Authentication
  url: https://developers.circle.com/w3s/authentication
- type: GettingStarted
  url: https://developers.circle.com/w3s/getting-started
- type: StatusPage
  url: https://status.circle.com/
- type: Support
  url: https://support.usdc.circle.com/
- type: Blog
  url: https://www.circle.com/blog
- type: Community
  url: https://discord.com/invite/buildoncircle
- type: GitHubOrganization
  url: https://github.com/circlefin
- type: PrivacyPolicy
  url: https://www.circle.com/legal/privacy-policy
- type: TermsOfService
  url: https://www.circle.com/legal/terms-of-service
- type: JSONLD
  url: json-ld/circle-context.jsonld
- type: JSONSchema
  url: json-schema/circle-wallet-schema.json
- type: JSONSchema
  url: json-schema/circle-transaction-schema.json
- type: AsyncAPI
  url: asyncapi/circle-webhooks-asyncapi.yml
- type: Spectral
  url: rules/circle-rules.yml
- type: LlmsText
  url: https://developers.circle.com/llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Circle API — frequently asked questions

Does Circle have an API?

Yes. APIs.io lists 2 APIs from Circle, including Gas Station and Paymaster and Circle Audit Logs API.

Is there an OpenAPI specification for the Circle API?

Yes. APIs.io indexes 1 OpenAPI specification for Circle, each linked for download from this page.

How do I authenticate with the Circle API?

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

How much does the Circle API cost?

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

Does Circle have an MCP server?

Yes. APIs.io lists 2 MCP servers for Circle: Remote MCP server at api.circle.com over HTTP; 4 tools listed.

Is the Circle API ready for AI agents?

Circle has a Kin Score of 41.1 out of 100 (developing) and an Agent Readiness score of 47.7 (agent-ready), scored by API Evangelist on 2026-11-06.

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Tools for providers

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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.
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