MetaMask

MetaMask is a leading self‑custodial cryptocurrency wallet and Web3 gateway. It enables users to manage crypto assets, interact with decentralized applications, and access a suite of developer tools such as SDKs, embedded wallets, smart accounts, and Snaps. The platform supports multiple blockchains including Ethereum, Solana, and Bitcoin, offering features like token swaps, perps trading, and on‑chain governance.

MetaMask is listed with 1 API on the APIs.io network: Token API. Tagged areas include Company, Cryptocurrency, Wallets, Web3, and Developer Tools.

The MetaMask catalog on APIs.io includes 1 Spectral governance ruleset.

MetaMask’s developer surface includes CLI, changelog, documentation, API reference, getting-started guide, support, engineering blog, and 19 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

23.5/100 emerging ▼ -9.4 Agent 28/100 agent aware Heartbeat 94/100 alive Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 API

Company Cryptocurrency Wallets Web3 Developer Tools

Kin Score

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

Composite quality — 23.5/100 · emerging

Contract Quality 1.8 / 19

Developer Ergonomics 6.3 / 15

Access Clarity 1.6 / 15

Operational Transparency 1.5 / 10

Contract Governance 1.6 / 9

Discoverability 4.9 / 8

Regulatory Posture 3.6 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 28/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 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 0 / 7

Rate-Limit Signaling 0 / 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 6 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 6 / 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 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/.

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

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
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
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
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)

9 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 9.4 — up to +22.7 composite points
Access Clarity scores 10.5 — up to +17.9 composite points
Developer Ergonomics scores 41.7 — up to +11.7 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/metamask/apis.yml: open an issue on github.com/api-evangelist/metamask 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 →

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.

Dynamic Client Registration

measured — observed by APIs.io (published)

OpenAPI

measured — observed by APIs.io (published)

APIs 1

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

MetaMask Token API

The Token API from MetaMask — 1 operation(s) for token.

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

MetaMask API Rules

9 rules · 7 errors 1 warnings 1 info

SPECTRAL

Security Posture 2

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

Metamask Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Metamask Vulnerability Disclosure

security.txt · contact published

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

WellKnown

WellKnown

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Spectral

Spectral

Conformance

Conformance

Build 5

SDKs, sample code, and the tooling you integrate with

CLI

CLI

SDKs

SDKs

Packages

Packages

GitHubOrganization

GitHubOrganization

Postman

Postman

Access & Security 4

Authentication, authorization, and security posture

SecurityTxt

SecurityTxt

Security

Security

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

ChangeLog

ChangeLog

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 3

The organization behind the API

Newsroom

Newsroom

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: metamask
name: MetaMask
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  probe_state: unreadable
  source:
  - security
  generated: '2026-11-06'
  method: derived
image: https://images.ctfassets.net/clixtyxoaeas/7Bth2z7E82BB90X6C3YG7m/7ddf5caae232ce3827e19eb2de646fa5/metamask-website-homepage.jpg
description: MetaMask is a leading self‑custodial cryptocurrency wallet and Web3 gateway. It enables users to manage crypto
  assets, interact with decentralized applications, and access a suite of developer tools such as SDKs, embedded wallets,
  smart accounts, and Snaps. The platform supports multiple blockchains including Ethereum, Solana, and Bitcoin, offering
  features like token swaps, perps trading, and on‑chain governance.
url: https://raw.githubusercontent.com/api-evangelist/metamask/refs/heads/main/apis.yml
x-type: company
x-source: harvest:tag-qc
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-13 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-13'
modified: '2026-10-13'
x-docs-platform: docusaurus
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-17
x-docs-hosting: vercel
tags:
- Company
- Cryptocurrency
- Wallets
- Web3
- Developer Tools
tags_raw:
- Company
- Crypto
- Wallet
- Web3
- DeveloperTools
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Spectral
  url: rules/metamask-rules.yml
- type: CLI
  url: cli/metamask-cli.yml
- type: Conformance
  url: conformance/metamask-conformance.yml
- type: LLMsTxt
  url: llms/metamask-llms.txt
- type: SecurityTxt
  url: well-known/metamask-security.txt
- type: WellKnown
  url: well-known/metamask-well-known.yml
- type: Hosts
  url: hosts/metamask-hosts.yml
- type: Vendors
  url: vendors/metamask-vendors.yml
- type: SDKs
  url: packages/metamask-packages.yml
- type: Packages
  url: packages/metamask-packages.yml
- type: Security
  url: https://metamask.io/security
- type: Newsroom
  url: https://metamask.io/news/how-to-buy-crypto
- type: ChangeLog
  url: https://github.com/MetaMask/snaps/releases
- type: VulnerabilityDisclosure
  url: security/metamask-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/metamask-domain-security.yml
- type: Website
  url: https://metamask.io
- type: DeveloperPortal
  url: https://metamask.io/developer
- type: Documentation
  url: https://docs.metamask.io
- type: APIReference
  url: https://docs.metamask.io
- type: GettingStarted
  url: https://metamask.io/download
- type: Support
  url: https://support.metamask.io/
- type: Blog
  url: https://metamask.io/news
- type: GitHubOrganization
  url: https://github.com/MetaMask
- type: TermsOfService
  url: https://metamask.io/terms
- type: PrivacyPolicy
  url: https://metamask.io/privacy
- type: Postman
  url: https://www.postman.com/metamask/workspace
apis:
- aid: metamask:metamask-token-api
  name: MetaMask Token API
  description: The Token API from MetaMask — 1 operation(s) for token.
  humanURL: https://docs.metamask.io/embedded-wallets/sdk/react/advanced/custom-authentication
  tags:
  - Tokens
  tags_raw:
  - Token
  properties:
  - type: OpenAPI
    url: openapi/metamask-token-api-openapi.yml
x-coverage:
  state: unreadable
  reason: js-rendered-docs
  detail: Docs at https://docs.metamask.io render via JavaScript and provide no machine‑readable spec.
  evidence:
  - url: https://docs.metamask.io/
    status: 200
  checked: '2026-10-13'
x-enrichment:
  date: '2026-10-13'
  status: enriched
  artifacts_added: 17
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

MetaMask API — frequently asked questions

Does MetaMask have an API?

Yes. APIs.io lists 1 API from MetaMask, including MetaMask Token API.

Is there an OpenAPI specification for the MetaMask API?

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

Is the MetaMask API ready for AI agents?

MetaMask has a Kin Score of 23.5 out of 100 (emerging) and an Agent Readiness score of 28.1 (agent-aware), scored by API Evangelist on 2026-11-06.

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