canonical: https://jentic.com/apis/1lookup.io/1lookup

# 1Lookup API

The 1Lookup API runs phone, email, IP, business, social, and SEO lookups from a single endpoint set backed by one shared credit balance. It validates and classifies phone numbers, scrubs them against Do Not Call and known-litigator lists, verifies email addresses, enriches contact records from an email, phone, or IP, and resolves company profiles and firmographics by domain. It also returns social profile checks, audience demographics, and SEO signals such as domain authority, backlinks, and keyword metrics. Every response uses one success-or-error envelope, so an agent reads the same shape whichever lookup it calls.

## For AI agents

Run phone, email, IP, business, social, and SEO lookups from one API: validate and scrub phone numbers, verify and enrich emails, resolve company profiles by domain, and pull domain SEO signals, all drawing on a single shared credit balance.

## Scope

Does not handle sending messages, placing calls, or storing CRM records. Use for phone, email, IP, business, social, and SEO data lookups only.

## Capabilities

- Validate a phone number and return its line type, carrier, location, and reachability
- Screen a phone number against spam, fraud, Do Not Call, and known-litigator lists
- Verify an email address and enrich a contact record from an email, phone, or IP
- Resolve company profiles, firmographics, and property records from a domain or address
- Return SEO signals for a domain: domain authority, backlink overview, and keyword metrics
- Check social profiles, audience demographics, and public posts by handle
- Skip-trace a name and address to a phone number, or reverse-look-up a number to a person

## Use cases

### Agent-Driven Contact Verification

An AI agent connected through Jentic verifies a contact before any outreach: it validates the phone number for line type and reachability, screens it against Do Not Call and litigator lists, and confirms the email address is deliverable. Because every lookup returns the same success-or-error envelope, the agent branches cleanly on the result without custom parsing per endpoint.

Example prompt: Validate a phone number, screen it against the DNC and litigator lists, then verify the contact's email address and report which checks passed

### Lead Enrichment Pipeline

A sales or RevOps workflow enriches a thin lead into a full record. Starting from an email address, the 1Lookup API enriches the contact, resolves the company profile and firmographics from the domain, and appends a phone number where one is known. The pipeline turns an email-only signup into a routable, scored lead without stitching together several vendors.

Example prompt: Enrich a contact from the `input` email address, resolve the company profile for its domain, and append a phone number if one is available

### Outbound Compliance Scrubbing

Before an outbound dialer or SMS campaign runs, each number is scrubbed against Do Not Call and known-litigator lists and classified by number type so landlines and VoIP numbers are handled correctly. The 1Lookup API charges only when a lookup returns data, so numbers with no match do not consume credits during a large scrub.

Example prompt: Scrub a list of phone numbers against the DNC and litigator lists and classify each number as mobile, landline, or VoIP

### Competitive SEO Research

A marketing agent gathers SEO intelligence on a competitor domain: it pulls domain authority, a backlink overview, keyword metrics, and search intent for a target query. The results feed content planning and link-building priorities, drawn from the same credit balance as the contact-data lookups.

Example prompt: Fetch the domain authority and backlink overview for a competitor domain and return keyword metrics for a target keyword

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| POST | `/phone` | Validate a phone number |
| POST | `/email` | Verify an email address |
| POST | `/email-enrichment` | Enrich a contact from an email address |
| POST | `/ip` | Look up an IP address |
| POST | `/company-profile-lookup` | Look up a company profile by domain |
| POST | `/domain-authority` | Get domain authority for a domain |
| POST | `/reverse-phone-lookup` | Reverse-look-up a phone number to a person or business |
| GET | `/account` | Read account status and credit balance |

## Key resources

- **Phone** — Validate, classify, spam-check, scrub, and reverse-look-up phone numbers
- **Email** — Verify, append, and enrich email addresses
- **Business** — Verify businesses and pull company profiles, firmographics, and property records
- **Social** — Check social profiles, audience demographics, and public posts
- **SEO** — Return domain authority, backlink overview, keyword metrics, and search intent

## AI readiness

This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.

- **Score:** 67 / 100
- **Maturity:** AI-Aware
- **Dimensions:**
  - Foundational Compliance: 99 / 100
  - Developer Experience & Jentic Compatibility: 71 / 100
  - AI-Readiness & Agent Experience: 46 / 100
  - Agent Usability: 94 / 100
  - Security: 60 / 100
  - AI Discoverability: 76 / 100
- **View full report:** https://jentic.com/apis/1lookup.io/1lookup/scorecard
- **How the score is calculated:** https://docs.jentic.com/reference/api-readiness-framework/overview/
- **More about the dimensions:** https://docs.jentic.com/reference/api-readiness-framework/specification/#dimensional-model-overview

### Score it yourself

Every API in the directory is allowlisted, so you can re-score it with no key required.

- **Score your own API:** https://jentic.com/scorecard.md
- **Scoring CLI agent skill:** https://github.com/jentic/jentic-api-scorecard/blob/main/skills/jentic-api-scorecard/SKILL.md

```sh
npx @jentic/api-scorecard-cli score <openapi-url>
```

## Why Jentic

- **Setup:** Wiring the 1Lookup API by hand means managing a bearer token, tracking the one shared credit balance that every phone, email, IP, business, social, and SEO lookup draws from, and handling rate-limit retries yourself. Through Jentic you install once, import the 1Lookup API from the API Directory, store the token once, and your agent calls it.
- **Permission scoping:** The 1Lookup API carries every lookup target in the request body, so a rule bounds which operations your agent may call, not which number or domain. You choose the operations it may call, so the higher-cost lookups like mobile-finder and skip-trace are not included unless you add them.
- **Credential handling:** Your 1Lookup bearer token is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
- **Discovery method:** Agents search Jentic by intent such as 'validate a phone number' or 'enrich a contact from an email', and Jentic returns the matching 1Lookup operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **Clearbit** — Clearbit enriches companies and people from an email or domain, similar to 1Lookup's business and contact lookups.
- **People Data Labs** — People Data Labs resolves person and company records at scale, overlapping with 1Lookup's contact enrichment.
- **Hunter** — Hunter finds and verifies email addresses for a domain, pairing well with 1Lookup's phone and firmographic data.
- **numverify** — numverify validates and classifies phone numbers, a narrower slice of 1Lookup's phone toolkit.

## FAQ

### What authentication does the 1Lookup API use?

The 1Lookup API authenticates with a bearer token sent in the Authorization header, per its OpenAPI spec. You mint the token in your 1Lookup account and send it with every lookup. Through Jentic the token is stored encrypted by your own Jentic One instance and injected at call time, so it never reaches the agent's prompt, logs, or context.

### Can I verify an email and find a contact's phone number with the 1Lookup API?

Yes. Email verification confirms an address is deliverable, and the enrichment lookups resolve a contact from an email, append a mobile number from an identifier, or skip-trace a name and address to a phone number. Each lookup draws from the same shared credit balance, and a lookup with no match does not consume a credit.

### What are the rate limits for the 1Lookup API?

The OpenAPI spec defines rate-limit response headers (a 429 response carries Retry-After and the remaining-request count) but does not state fixed numeric limits. Check https://www.1lookup.io for the current limits that apply to your plan.

### Is there a 1Lookup MCP server?

Yes, 1Lookup offers a hosted MCP server. You can also connect the 1Lookup API directly through Jentic: your agent gets the full 43-endpoint surface without loading another server's tool definitions into its context, your credential is injected at call time by your self-hosted instance instead of living in an MCP config, and your rules decide which operations the agent may call.

### Can I limit what my agent is allowed to do with the 1Lookup API?

Yes. Because every lookup carries its target in the request body, you write a rule that allows just the operations the agent needs, such as phone validation and email verification, and leave out the higher-cost reverse-lookup, mobile-finder, and skip-trace operations. The agent can then run those checks and nothing else, and every call it makes is logged.

### How do I enrich a contact from an email with the 1Lookup API through Jentic?

Import the 1Lookup API from the Jentic API Directory, store your bearer token once, and have your agent search Jentic for 'enrich a contact from an email'. Jentic returns the email-enrichment operation with its input schema, so the agent sends the `input` field and reads the enriched record. To run it on your own infrastructure, install Jentic One from its GitHub repo.

### Does the 1Lookup API charge credits per lookup?

Yes. One shared credit balance covers every product, most lookups cost one credit, and higher-cost lookups such as skip-trace and mobile-finder cost more. Failed processing, and lookups that return no match, consume no credits, and the account endpoint reports your current balance.