name: 1Lookup
description: >-
  1Lookup is a self-serve data verification and enrichment platform for SMBs, exposing more than forty
  products through a single REST API and one universal credit balance. It validates phone numbers (line
  type, carrier, HLR reachability, number portability, DNC status, spam/scam reputation, fraud score),
  email addresses (syntax, MX, deliverability, disposable and role-based detection) and IP addresses
  (geolocation, VPN/proxy/Tor and datacenter detection), then extends into B2B company and contact data
  (firmographics, prospect and account search, contact append, skip trace), SEO and web intelligence
  (domain authority, backlinks, keyword metrics, audience reports, SERP and website scraping), social and
  media lookups, property data and audio transcription. The same engine powers a web dashboard with batch
  CSV validation, roughly twenty-five free rate-limited browser tools, and a first-party hosted MCP
  connector authorized with OAuth 2.1 that gives AI agents five of the core tools without an API key.
image: https://www.1lookup.io/images/featured/pages/homepage.png
url: https://raw.githubusercontent.com/api-evangelist/1lookup/refs/heads/main/apis.yml
created: '2026-08-08'
modified: '2026-08-14'
specificationVersion: '0.21'
tags:
  - phone validation
  - email validation
  - IP intelligence
  - fraud & risk
  - data enrichment
  - B2B contact & company data
  - SEO / web analytics
  - audio transcription
  - MCP / agent-native
  - REST API
apis:
  - name: 1Lookup REST API
    description: >-
      RESTful API over HTTPS covering all 1Lookup products (phone/email/IP validation, fraud, enrichment,
      B2B data, SEO intelligence). API-key Bearer auth (sk_live_ keys, organization-scoped), JSON bodies,
      one response envelope on every product, and job-based bulk processing up to 100,000 rows with an
      Idempotency-Key contract and signed webhook callbacks. 46 documented operations, almost all POST,
      priced against a universal credit balance. No OpenAPI or other machine-readable contract is
      published.
    humanURL: https://app.1lookup.io/api
    baseURL: https://app.1lookup.io/api/v1
    tags:
      - phone validation
      - email validation
      - IP intelligence
      - fraud & risk
      - data enrichment
      - B2B contact & company data
      - SEO / web analytics
      - audio transcription
      - REST API
    properties:
      - type: Documentation
        url: https://app.1lookup.io/api
      - type: APIReference
        url: https://app.1lookup.io/api#endpoints
      - type: GettingStarted
        url: https://app.1lookup.io/api#getting-started
      - type: Authentication
        url: authentication/1lookup-authentication.yml
      - type: Conventions
        url: conventions/1lookup-conventions.yml
      - type: ErrorCatalog
        url: errors/1lookup-problem-types.yml
      - type: RateLimits
        url: rate-limits/1lookup-rate-limits.yml
      - type: Lifecycle
        url: lifecycle/1lookup-lifecycle.yml
      - type: Idempotency
        url: conventions/1lookup-conventions.yml
      - type: Webhooks
        url: asyncapi/1lookup-webhooks.yml
      - type: DataModel
        url: data-model/1lookup-data-model.yml
      - type: Examples
        url: examples/1lookup-examples.yml
  - name: 1Lookup MCP Server
    description: >-
      First-party hosted/remote MCP connector with OAuth 2.1 auth (authorization code + PKCE, dynamic
      client registration, single `lookup` scope) exposing 5 tools (validate_phone, verify_email,
      ip_lookup, bulk_verify, get_account) for Claude, Cursor, ChatGPT, and any MCP client. Tool calls
      bill against the same plan credits as the REST API.
    humanURL: https://www.1lookup.io/products/mcp
    baseURL: https://app.1lookup.io/api/mcp
    tags:
      - MCP / agent-native
      - phone validation
      - email validation
      - IP intelligence
    properties:
      - type: MCPServer
        url: https://app.1lookup.io/api/mcp
      - type: MCPServer
        url: mcp/1lookup-mcp.yml
      - type: ToolCrosswalk
        url: mcp/1lookup-tool-crosswalk.yml
      - type: Documentation
        url: https://www.1lookup.io/products/mcp
      - type: OAuthScopes
        url: scopes/1lookup-scopes.yml
      - type: WellKnown
        url: https://www.1lookup.io/.well-known/mcp/server-card.json
  - name: 1Lookup LLMs Index
    description: >-
      Machine-readable content indexes (llms.txt and llms-full.txt) for AI and answer engines, indexing
      the free tools, every product page, the comparison pages and the key site sections.
    humanURL: https://www.1lookup.io
    baseURL: https://www.1lookup.io
    tags:
      - MCP / agent-native
    properties:
      - type: LLMsTxt
        url: https://www.1lookup.io/llms.txt
      - type: LLMsTxt
        url: https://www.1lookup.io/llms-full.txt
      - type: LLMsTxt
        url: llms/1lookup-llms.txt
maintainers:
  - FN: 1Lookup
    url: https://www.1lookup.io
    email: support@1lookup.io
generated:
  by: apis.io/add
  model: claude-opus-4-8
  confidence: 93
  at: '2026-08-08T11:53:32.811Z'
common:
- type: DeveloperPortal
  url: https://app.1lookup.io/api
- type: Documentation
  url: https://app.1lookup.io/api
- type: APIReference
  url: https://app.1lookup.io/api#endpoints
- type: GettingStarted
  url: https://app.1lookup.io/api#getting-started
- type: Website
  url: https://www.1lookup.io
- type: Blog
  url: https://www.1lookup.io/blog
- type: Support
  url: https://www.1lookup.io/contact
- type: Pricing
  url: https://www.1lookup.io/pricing
- type: SignUp
  url: https://app.1lookup.io/signup
- type: Login
  url: https://app.1lookup.io/login
- type: TermsOfService
  url: https://www.1lookup.io/terms
- type: PrivacyPolicy
  url: https://www.1lookup.io/privacy
- type: FAQ
  url: https://www.1lookup.io/faq
- type: Integrations
  url: https://www.1lookup.io/integrations
- type: Glossary
  url: https://www.1lookup.io/glossary
- type: LinkedIn
  url: https://linkedin.com/company/1lookup
- type: Twitter
  url: https://x.com/1LookupApp
- type: YouTube
  url: https://www.youtube.com/@1LookupApp
- type: Authentication
  url: authentication/1lookup-authentication.yml
- type: OAuthScopes
  url: scopes/1lookup-scopes.yml
- type: Conventions
  url: conventions/1lookup-conventions.yml
- type: ErrorCatalog
  url: errors/1lookup-problem-types.yml
- type: RateLimits
  url: rate-limits/1lookup-rate-limits.yml
- type: Plans
  url: plans/1lookup-plans-pricing.yml
- type: Lifecycle
  url: lifecycle/1lookup-lifecycle.yml
- type: Conformance
  url: conformance/1lookup-conformance.yml
- type: Compliance
  url: https://www.1lookup.io/security
- type: TrustCenter
  url: security/1lookup-trust-center.yml
- type: Security
  url: https://www.1lookup.io/security
- type: VulnerabilityDisclosure
  url: security/1lookup-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/1lookup-domain-security.yml
- type: WellKnown
  url: well-known/1lookup-well-known.yml
- type: Packages
  url: packages/1lookup-packages.yml
- type: Sandbox
  url: sandbox/1lookup-sandbox.yml
- type: MCPServer
  url: mcp/1lookup-mcp.yml
- type: ToolCrosswalk
  url: mcp/1lookup-tool-crosswalk.yml
- type: LLMsTxt
  url: llms/1lookup-llms.txt
- type: AgentSkill
  url: skills/_index.yml
- type: Idempotency
  url: conventions/1lookup-conventions.yml
- type: Webhooks
  url: asyncapi/1lookup-webhooks.yml
- type: DataModel
  url: data-model/1lookup-data-model.yml
- type: Examples
  url: examples/1lookup-examples.yml
x-enrichment:
  date: '2026-08-14'
  status: enriched
  artifacts_added: 5
  artifacts_updated: 14
  pass: local-v1
  note: >-
    1Lookup rewrote its API reference between 2026-08-09 and 2026-08-14: an Idempotency-Key contract on
    bulk jobs, a signed webhook surface, a thirteen-code error registry, X-Request-Id, Retry-After, a
    four-tier rate-limit model, a versioning policy, two new products, and a machine-readable MCP server
    card at www.1lookup.io/.well-known/mcp/server-card.json. Still no OpenAPI and no A2A agent card.