Data Validation – Free-tier APIs
15 Free-tier APIs in the category Data Validation. Free public web APIs that developers and AI agents can call. Entries come from the open public-apis list; each link was checked automatically (HTTP status) on the date shown, which says the site responded, not that the API is good.
Attestwire
Validate EN 16931 e-invoices: XRechnung, ZUGFeRD, Factur-X, Peppol BIS
invowerk
Validate e-invoices (ZUGFeRD, Factur-X, XRechnung, Peppol BIS) and get a validation report
Lob.com
US Address Verification
Postman Echo
Test api server to receive and return value from HTTP method
RevAddress
US address standardization, congressional and state legislative districts, Census data; free tier
SchemaShield
Read-only preflight for breaking schema changes and downstream query impact
sthan.io Address Autocomplete
Real-time US address suggestions as users type
sthan.io Address Parser
Parse freeform US addresses into structured fields (house number, street, unit, city, state, ZIP)
sthan.io Address Verification
Validate and standardize US addresses, with ZIP+4 and deliverability status
Temsor
Validates Turkish national ID, tax number, IBAN, phone, plate and parses addresses
US Autocomplete
Enter address data quickly with real-time address suggestions
US Extract
Extract postal addresses from any text including emails
US Street Address
Validate and append data for any US postal address
VATlayer
VAT number validation
VerifNow
Validates email, phone, IBAN, EU VAT against VIES, and Canadian, Spanish and US national IDs