E.164 phone number format: a practical developer guide
Learn the E.164 phone number format, country codes, trunk-prefix removal, storage rules and common implementation mistakes.
Read guideEngineering reference
Phone number developer guides
Build safer international phone inputs, validation pipelines, storage models and test datasets from standards-based principles.
Phone number validation: what to check and when
A practical guide to phone number normalization, structural validation, reachability checks and production validation architecture.
Read guideHow to create safer phone number test data
Create safer phone number test data using reserved fictional ranges, deterministic fixtures and explicit invalid cases.
Read guideDesigning an international phone number input
Design an international phone number field that handles country context, pasted formatting, validation, accessibility and canonical storage.
Read guidePhone number regex: useful checks without false confidence
Learn when a phone number regex is useful, why one global pattern fails and how to test JavaScript expressions safely.
Read guideRFC 3966 tel URIs: building reliable telephone links
Build valid tel links with global numbers, extensions and parameters using the RFC 3966 telephone URI format.
Read guideHow to store phone numbers in a database
Design database fields for E.164 phone numbers, extensions, verification state, uniqueness, encryption and display formatting.
Read guideCountry calling codes: how to parse them correctly
Understand country calling codes, shared plans, trunk prefixes and safe international phone-number parsing.
Read guidePhone number formatting in JavaScript
Format international phone numbers in JavaScript with country context, E.164 storage, as-you-type UX and maintained numbering metadata.
Read guideHow to handle phone number extensions
Handle phone number extensions safely in forms, databases and RFC 3966 tel links without corrupting the E.164 value.
Read guidePhone number testing checklist
Use a practical phone number testing checklist for parsing, formatting, validation, storage, forms, APIs and safe delivery workflows.
Read guidePhone number masking and safe logging
Mask phone numbers in user interfaces, logs and analytics while preserving canonical data, access controls and useful operational signals.
Read guideOriginal research and maintenance
See how the fixtures are reviewed
Fixture methodology
Source hierarchy, safety labels, review steps and known limits for the 31-country dataset.
Read the methodologyFictional range review
A source-linked comparison of documented creative-use examples and structural fixtures.
Open the safety matrixE.164 test cases
Six explicit inputs, regions and expected canonical outputs with failure boundaries.
Reproduce the casesDataset changelog
Material source, schema, URL and editorial changes recorded by date.
View the changelogValidation lab
Separate parsing, possible structure, allocation, reachability and user control.
Run the validation modelUse the interactive tools
Put the concepts into practice with local browser tools for formatting, validation, regular expressions, calling codes and bulk fixtures.
Browse all tools