1Lookup

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.

1Lookup publishes 3 APIs on the APIs.io network. Tagged areas include Phone Validation, Email Validation, IP Intelligence, Fraud and Risk, and Data Enrichment.

The 1Lookup catalog on APIs.io includes 1 event-driven AsyncAPI specification.

1Lookup’s developer surface includes documentation, API reference, getting-started guide, engineering blog, support, pricing, signup flow, and 34 more developer resources.

🌐 Visit website 📡 Source on GitHub

61.6/100 strong ▬ flat Agent 55/100 agent native saas Full breakdown ↓
scored 2026-09-06 · rubric v0.19.0

AccessPaidOpenFree trial⚡ Free to try

3 APIs 2 MCP Servers

Phone Validation Email Validation IP IntelligenceFraud and RiskData EnrichmentB2B contact & company dataSEO / web analyticsAudio TranscriptionMCP / agent-nativeREST API

Kin Score

Kin Score How this is scored →
scored 2026-09-06 · rubric v0.19.0

Composite quality — 61.6/100 · strong

Contract Quality 12.0 / 25

Developer Ergonomics 13.2 / 20

Access Clarity 18.4 / 20

Operational Transparency 6.5 / 13

Contract Governance 2.2 / 12

Discoverability 9.3 / 10

Agent readiness — 55/100 · agent native

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 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 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 6

Agentic Commerce Well-Known Document 0 / 5

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/1lookup: 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 3

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

MCP Servers 2

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

Rate Limits 1

Documented rate limits and quota policies.

Scopes 1

OAuth scopes governing access to this provider's APIs.

1Lookup Scopes

1 scope · authorizationCode

1 scopes

SCOPES

Resources

Get Started 5

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Sandbox

Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

WellKnown

MCPServer

LLMsTxt

AgentSkill

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

Lifecycle

Conformance

Idempotency

Webhooks

DataModel

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

Packages

Packages

ToolCrosswalk

ToolCrosswalk

Examples

Examples

Access & Security 7

Authentication, authorization, and security posture

Authentication

OAuthScopes

Compliance

TrustCenter

Security

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Scroll for all 7

Learn 1

Tutorials, courses, talks, and written guidance

YouTube

YouTube

Operate 3

Status, limits, changes, and where to get help

Support

Support

FAQ

FAQ

RateLimits

RateLimits

Commercial 4

Pricing, plans, and the legal terms of use

Pricing

TermsOfService

PrivacyPolicy

Plans

Company 4

The organization behind the API

Website

Website

Blog

Blog

LinkedIn

Twitter

Twitter

Other 1

Properties that don't map to a standard resource type

Glossary

Glossary

Source (apis.yml)

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.
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: paid
  onboarding: open
  trial: true
  try_now: true
  public: true
  label: Paid (free trial) · Open access
  confidence: high
  source:
  - plans
  - authentication
  - scopes
  - rate-limits
  - security
  - sandbox
  generated: '2026-09-02'
  method: derived
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: '0.23'
tags:
- Phone Validation
- Email Validation
- IP Intelligence
- Fraud and Risk
- Data Enrichment
- B2B contact & company data
- SEO / web analytics
- Audio Transcription
- MCP / agent-native
- REST API
tags_raw:
- 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 and Risk
  - Data Enrichment
  - B2B contact & company data
  - SEO / web analytics
  - Audio Transcription
  - REST API
  tags_raw:
  - 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
  tags_raw:
  - 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.'

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1Lookup

Kin Score

APIs 3

1Lookup REST API

1Lookup MCP Server

1Lookup LLMs Index

MCP Servers 2

1Lookup MCP Server

1Lookup MCP Server

Pricing Plans 1

1Lookup Plans Pricing

Rate Limits 1

1Lookup Rate Limits

Event Specifications 1

1Lookup Webhooks

Security Posture 4

1Lookup Authentication

1Lookup Domain Security

1Lookup Vulnerability Disclosure

1Lookup Trust Center

Scopes 1

1Lookup Scopes

Resources

Get Started 5

Documentation 2

Agent Surfaces 4

Design & Contract 7

Build 3

Access & Security 7

Learn 1

Operate 3

Commercial 4

Company 4

Other 1

Source (apis.yml)

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