Phone Number Lookup API — Append Verified Phones to Names and Addresses

What is a Phone Number Lookup API?

A phone number lookup API takes identity information — typically a full name plus a known address or city/state — and returns one or more verified phone numbers associated with that person. It is the programmatic equivalent of hiring a PI to track down a current contact number, delivered as a REST endpoint at a cost of two cents per successful match.

Ava Data's phone number lookup is built on the same PI-grade identity graph used by professional investigators: it aggregates data across public records, utility registrations, credit header files, and proprietary identity networks, then refreshes every 24 hours. A phone that disconnected last week shows up as disconnected today — not next quarter when your call campaign starts logging wrong-number dispositions at scale.

Internal links: Skip Tracing API · Contact Enrichment API · Bulk Skip Tracing · People Search API glossary · What is skip tracing?

Data Sources and Refresh Cadence

Most phone append services source their data from a small number of aggregators who themselves pull from public records on a quarterly or annual schedule. By the time a phone number works its way from a utility company's address change to your lookup API, it may be six to eighteen months old. For residential real estate or any workflow targeting people who move frequently, that lag is significant.

Ava Data maintains a proprietary identity graph that refreshes every 24 hours across multiple independent data streams. When someone changes their number, registers at a new address, or appears in a new record, that signal reaches our graph within a day rather than a quarter. The result is a meaningfully higher connect rate — not just a higher match rate — because the numbers we return are current at the time of the lookup.

Each phone number in the response is tagged with a type (mobile, landline, VOIP) and a confidence score so you can prioritize dialing order. Mobile numbers with high confidence scores connect at the highest rates and can be sequenced first in your dialer.

Pricing

Phone-only lookups use the 1-credit Standard tier ($0.02 per match). If you also need the email address, select the 2-credit tier. If you need to reach someone through a spouse or associate because direct contact attempts have failed, Deep Search (10 credits) returns the full relational graph with contact info for each person.

API Integration

The endpoint accepts JSON over HTTPS with a bearer token in the Authorization header. The minimal request body is first name, last name, and either a full address or a city and state. Additional fields (middle name, zip code) improve match accuracy when available.

{
  "firstName": "Maria",
  "lastName": "Santos",
  "address": "8820 Sunset Blvd",
  "city": "Los Angeles",
  "state": "CA",
  "returns": ["phone"]
}

{
  "matchFound": true,
  "creditsCharged": 1,
  "subject": {
    "firstName": "Maria",
    "lastName": "Santos",
    "phones": [
      { "number": "+13105550071", "type": "mobile", "confidence": "high" },
      { "number": "+13235550134", "type": "landline", "confidence": "medium" }
    ]
  }
}

The response returns all matched phone numbers sorted by confidence. Most implementations take the first number (highest confidence) and write it to the CRM field, but you can store all numbers for fallback dialing sequences.

Common Use Cases

• Real estate lead enrichment: Append direct phone numbers to absentee-owner or tax-delinquent lists before handing off to a dialer. See Skip Tracing for Real Estate Investors →
• CRM backfill: Enrich existing contacts in your CRM where the phone field is missing or the stored number is no longer in service.
• Outbound sales prospecting: Append verified mobile numbers to prospect lists built from name + company data before a call campaign.
• Debt collection and recovery: Locate current contact numbers for accounts where the debtor's contact info on file is stale.
• Tenant screening and landlord lookups: Verify contact information for applicants or locate previous tenants. See Landlord Skip Tracing →

For high-volume enrichment, use the bulk CSV processing endpoint to process thousands of records in a single async job rather than making individual API calls per record.