Signal Lookup by Phone Number
View All Signal Number Validation & Profile Lookup APIs →Check whether a phone number is registered on Signal and, when registered, return its public profile in one call: display name, given/family name, About bio, canonical E.164 phone, stable ACI and PNI UUIDs, avatar color, registration status, and flags (isBlocked, isSelf, showVerified, isProfileSharing). Pass the full international number (digits, with country code); the API normalizes to digits only. When the number has no Signal account, registered=false is returned.
API Features
Real-time registration check Instantly know whether a phone number has a Signal account via a clear registered=true/false result
Public profile fields When registered, returns display name, given/family name, About bio, E.164 phone, and avatar color
Stable identifiers (ACI/PNI) Returns ACI and PNI UUIDs you can use for deduplication, linking, and identity resolution
Trust & risk flags isBlocked, showVerified, isProfileSharing, isSelf help with trust and risk signals
Live API Demo
API Response (JSON)
{} Query Result
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Use Cases
- Lead and contact validation: verify numbers are on Signal before outreach or enrichment
- Identity resolution: use stable ACI/PNI UUIDs to deduplicate and link records
- Risk and trust scoring: leverage verified/blocked flags in fraud or quality checks
- Contact enrichment: append Signal display name and About to CRM records