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libphonenumber-csharp

9.0.40106M downloads/motwcclegg/libphonenumber-csharp ↗New releases in your daily digest, changelog included.

C# port of Google's common Java, C++ and Javascript library for parsing, formatting, storing and validating international phone numbers. https://github.com/google/libphonenumber

Last release 14 days ago
24 Sep 2026
Ships on a steady schedule
a new release about every 2 weeks
Some releases are documented
notes for 29 of the last 60 stable releases
4 versions withdrawn
withdrawn after publishing
127 years old
259 releases · first in 1900

Release timeline

259 releases since 1900

Releases

9.0.4024 Sept 2026
libphonenumber-csharp 9.0.40 · libphonenumber-csharp.extensions 9.0.40 · upstream v9.0.40
libphonenumber-csharp 9.0.40 · libphonenumber-csharp.extensions 9.0.40 · upstream v9.0.40

What's Changed

feat: fold the changelog by authorship, and attribute the sync commit by @twcclegg in #471

feat: open the metadata sync as a PR for review instead of merging it unattended by @twcclegg in #464

docs: break down AGENTS.md into various useful reusable skills to follow best practice by @wmundev in #472

feat: extract svgs in the demo website to reusable components instead of inlining them everywhere by @wmundev in #473

feat: add DocFX API reference site, published alongside the demo by @twcclegg in #453

docs: mark the metadata tree generated, and say not to read it by @twcclegg in #477

fix: demo initial-load focus ring, theme-synced favicon, and icon/alignment polish by @twcclegg in #455

feat: automatic upgrade to v9.0.40 by @libphonenumber-csharp-bot in #479

Full Changelog: v9.0.39...v9.0.40

9.0.3910 Sept 2026

libphonenumber-csharp 9.0.39 · libphonenumber-csharp.extensions 9.0.39 · upstream v9.0.39

What's Changed

fix: replace non-existent min() with the && / || ternary idiom in fuzz.yml by @twcclegg in #436
chore: gitignore local Claude Code worktree scratch state by @twcclegg in #442
docs: require explicit sign-off before adding new public API surface by @twcclegg in #447
perf: narrow \d to ASCII [0-9] in metadata-matched regex patterns by @twcclegg in #446
docs: add API differences from upstream Java reference by @twcclegg in #439
refactor: replace the benchmark-comparison JS files with C# and bash by @twcclegg in #444
Extensions: Native AOT JsonSerializerContext + formatting extension methods by @twcclegg in #440
perf(test): add first-use-per-region cold-start benchmark by @twcclegg in #438
docs: add CHANGELOG.md (back to v8.7.1) and auto-update it on release by @twcclegg in #441
docs: PR descriptions describe current state, not their own history by @twcclegg in #449
Bump the nuget_minor_patch_updates group with 2 updates by @dependabot[bot] in #452
chore(deps): bump actions/setup-java from 5.6.0 to 6.0.0 by @dependabot[bot] in #451
chore(deps): bump the codeql-action group with 3 updates by @dependabot[bot] in #450
fix: mark IMetadataLoader/SetMetadataLoader obsolete, not internal by @twcclegg in #448
perf: stop compiling metadata-derived regexes by @twcclegg in #445
docs: move agent guidance to AGENTS.md, point CLAUDE.md at it by @twcclegg in #454
refactor: simplify IsLatinLetter range test, document broad catch by @twcclegg in #461
fix: stop MetadataFilter.GetHashCode throwing on an empty blacklist by @twcclegg in #462
fix: make MetadataFilter.GetHashCode agree with Equals for non-empty blacklists by @twcclegg in #465
refactor: match upstream grouping in FormatNumberForMobileDialing by @twcclegg in #463
ci: harden metadata release and triage workflow permissions by @twcclegg in #458
fix: stop the obsolete leading-zero setter calling an obsolete method by @twcclegg in #460
fix: make national-prefix stripping's null handling provable by @twcclegg in #459
fix: make the documented demo test command actually run tests by @twcclegg in #456
docs: extend CHANGELOG.md back through the C# port's pre-v8.7.1 history by @twcclegg in #466
ci: strip generated-code results from CodeQL SARIF before upload by @twcclegg in #457
ci: stop persisting git credentials in checkouts that don't use them by @twcclegg in #468
perf: sparse-checkout the two workflows that only read a handful of files by @twcclegg in #467
perf: stop vendoring upstream's metadata csv tables by @twcclegg in #469
feat: automatic upgrade to v9.0.39 by @libphonenumber-csharp-bot in #470

Full Changelog: v9.0.38...v9.0.39

Open source →

Additional notes

Includes the metadata sync to upstream libphonenumber v9.0.39 plus other changes merged to main since the last release — see the compare link above for the full diff.

Open source →

9.0.3828 Aug 2026

libphonenumber-csharp 9.0.38 · libphonenumber-csharp.extensions 9.0.38 · upstream v9.0.38

What's Changed

docs: refresh the docs for the binary metadata, build and CI changes by @twcclegg in #391
Close the Scorecard token-permission and unpinned-restore findings by @twcclegg in #387
build: drop restore lock files and locked-mode CI restores by @twcclegg in #396
perf: move the locale country names out of generated C# into binary resources by @twcclegg in #395
fix: scope the locale name aliases to their own country by @twcclegg in #397
build: compare both packages against the 9.0.37 baseline by @twcclegg in #394
ci: build once for test and pack instead of compiling the library twice by @twcclegg in #393
Migrate to slnx; lift AngleSharp clear of GHSA-pgww-w46g-26qg by @twcclegg in #388
chore: move the locale generator to temurin 25 by @twcclegg in #398
feat: fuzz the parsing surface with FsCheck properties and SharpFuzz by @twcclegg in #392
ci: attest build provenance for the published packages by @twcclegg in #400
test: port the upstream IsPossibleNumberForType tests by @twcclegg in #399
docs: reconcile stale Todo sections with current state by @twcclegg in #403
test: exclude the ported protobuf-style Builder classes from coverage by @twcclegg in #410
ci: skip dotnet's first-time-experience setup in run_performance_tests by @twcclegg in #411
ci: exclude generated obj/ from CodeQL, document the second empty catch by @twcclegg in #407
fix: NumberParseException instead of ArgumentOutOfRangeException on malformed RFC3966 phone-context ordering by @twcclegg in #406
internal: BinaryPrimitives in ByteBuffer, volatile singleton instance by @twcclegg in #404
fix: cap AsYouTypeFormatter growth and guard PhoneNumberUtil against null by @twcclegg in #402
Fix three matcher/formatter parity gaps vs. upstream Java source by @twcclegg in #408
feat(extensions): TryParse overloads, TypeConverter, and a real phone-number ValidationAttribute by @twcclegg in #405
style: small idiomatic-C# cleanups (no behavior change) by @twcclegg in #409
style: idiomatic cleanups in mid-size test files by @twcclegg in #421
style: idiomatic cleanups in matcher/formatter/filter test suites by @twcclegg in #420
style: minor idiomatic cleanups in protobuf-style data model classes by @twcclegg in #415
style: idiomatic cleanups in ShortNumberInfo by @twcclegg in #412
style: idiomatic cleanups in metadata build tooling by @twcclegg in #413
style: idiomatic cleanups in small metadata/storage utility files by @twcclegg in #414
style: idiomatic cleanups in AsYouTypeFormatter and PhoneNumberMatcher by @twcclegg in #416
style: idiomatic cleanups in PhoneNumberUtil.cs by @twcclegg in #418
style: idiomatic cleanups in PhoneNumberUtil platform partials by @twcclegg in #417
internal: seal singleton-style types with no accessible constructor by @twcclegg in #424
Fix cs/xmldoc/missing-summary: wrap bare doc comments in by @twcclegg in #427
ci: manual CodeQL dispatch + consolidated full-repo findings by @twcclegg in #423
ci: only report statistically significant benchmark changes by @twcclegg in #425
Add automated triage bot for metadata-only issues by @twcclegg in #422
Fix path traversal in BuildLocaleNames and uncaught parse exception in PhoneNumberTypeConverter by @twcclegg in #428
Fuzz: exercise the selected region in FormatOutOfCountryCallingNumber, cap manual duration by @twcclegg in #429
feat: rework metadata sync to PR + auto-merge by @twcclegg in #431
fix: authenticate the metadata-update PR as the bot account, not GITHUB_TOKEN by @twcclegg in #434
feat: automatic upgrade to v9.0.38 by @libphonenumber-csharp-bot in #435

New Contributors

@libphonenumber-csharp-bot made their first contribution in #435

Full Changelog: v9.0.37...v9.0.38

Open source →

Additional notes

A larger-than-usual release: the metadata-sync automation itself was reworked, alongside a batch of Extensions API additions, security/hardening fixes, and a large internal code-quality pass.

Added

(Extensions) PhoneNumber.TryParse/TryParseValid 2-argument overloads matching the conventional .NET TryParse shape; PhoneNumberTypeConverter for TypeConverter-based binding (config binding, PropertyGrid, etc.); PhoneNumberAttribute, a DataAnnotations ValidationAttribute backed by real validation (PhoneNumberUtil.IsValidNumber) instead of the framework's loose [Phone] regex. (#405)
A SharpFuzz/FsCheck-based fuzzing target for the parsing surface (PhoneNumbers.Fuzz, not part of the solution, run weekly by fuzz.yml). (#392)
Build-provenance attestation for the published NuGet packages. (#400)

Changed

Metadata-sync automation now opens a PR (authenticated as a dedicated libphonenumber-csharp-bot account, not the ambient GITHUB_TOKEN) and auto-merges it, instead of pushing straight to main. (#431, #434) finalize_metadata_release.yml then tags the merge commit and dispatches the NuGet publish. This CHANGELOG's own entries are now written into that same commit by the sync script.
Migrated the solution file to the .slnx format. (#388)
Upgraded bUnit to 2.x, clearing a transitive AngleSharp advisory (GHSA-pgww-w46g-26qg). (#398)
Moved the locale country-names table out of generated C# and into a binary resource per country, read on demand by LocaleNames (mirrors the phone/short-number/geocoding "binary metadata" move from v9.0.29–v9.0.32, below); LocaleData still exposes the whole table for callers outside the library. (#395)
Dropped the restore lock files and locked-mode CI restores added the previous release (v9.0.37) — they didn't earn their complexity; NuGetAudit and pinned-exact-versions-in-Directory.Packages.props do the job restore locking was meant for. (#396) Package-validation baselines for both packable projects now compare against the 9.0.37 release. (#394)
A large batch of purely internal idiomatic-C# cleanups (is-null pattern matching, TryGetValue, LINQ Select/Where, ??=, sealing singleton-style types, BinaryPrimitives in ByteBuffer) and CodeQL-driven fixes (redundant ToString()/GetHashCode() calls, GetType() comparisons, invariant-culture formatting) — no behavior change. (#409, #412–#421, #424 and others)
CodeQL now runs on manual dispatch as well as its schedule, and excludes generated obj/ output. (#407, #423)

Fixed

Security: a path-traversal issue in BuildLocaleNames and an uncaught parse exception in PhoneNumberTypeConverter. (#428)
NumberParseException (rather than ArgumentOutOfRangeException) on malformed RFC3966 phone-context ordering. (#406)
Several PhoneNumberMatcher/AsYouTypeFormatter parity gaps against the upstream Java source, including formattingRuleHasFirstGroupOnly and containsMoreThanOneSlashInNationalNumber. (#408)
Unbounded growth in AsYouTypeFormatter and missing null-guards in PhoneNumberUtil. (#402)
FormatOutOfCountryKeepingAlphaChars no longer throws when region metadata is missing.

Docs

Reconciled stale Todo sections and refreshed documentation for the binary-metadata, build, and CI changes made across v9.0.29–v9.0.38.

9.0.3714 Aug 2026

libphonenumber-csharp 9.0.37 · libphonenumber-csharp.extensions 9.0.37 · upstream v9.0.37

What's Changed

fix: pin the release tag to the commit just pushed by @twcclegg in #369
Modernization: stack-overflow fix, frozen collections, drop net9.0, centralized build config by @twcclegg in #370
build(deps): bump ossf/scorecard-action from 2.4.3 to 2.4.4 by @dependabot[bot] in #371
Add offline geocoder benchmarks, and fix the crash they exposed by @twcclegg in #372
Cache NuGet packages, enable lock files and package validation by @twcclegg in #373
Read the flyweight map buffer from an array instead of a stream by @twcclegg in #376
Raise analysis on the library, and fix what it found by @twcclegg in #374
Filter the benchmark job, drop netframework4.8, pin nuget sources by @twcclegg in #377
Check the public surface survives hostile input by @twcclegg in #379
Measure the parse, validate and format phases separately by @twcclegg in #378
Benchmark the input shapes callers actually supply by @twcclegg in #381
Match slices without materialising them when parsing by @twcclegg in #382
Capture every extension alternative into one named group by @twcclegg in #383
Skip the match groups when stripping a national prefix by @twcclegg in #384
Strip the national prefix without materialising a match by @twcclegg in #385
Don't render the country calling code test to strings by @twcclegg in #386
fix: ship symbols in a .snupkg instead of embedding them in the assembly by @twcclegg in #390

Full Changelog: v9.0.36...v9.0.37

Open source →

Additional notes

A dedicated performance-optimization release, alongside build-reproducibility and package-validation work and new benchmark coverage.

Performance

A long series of allocation- and regex-reduction changes on the parsing/formatting hot path: matching against slices instead of materializing them, skipping regex match groups when stripping a national prefix, capturing every extension alternative into one named group, truncating the lookup prefix by integer division instead of a string round-trip, reading the flyweight prefix-map buffer from an array instead of a stream, and not rendering the country-calling-code test to a string.
Froze the country-calling-code-to-region-code map and the short-number/timezone lookup tables into frozen collections; sized the Normalize stack buffer to the input instead of a fixed allocation.

Added

Benchmarks for the offline geocoder (previously untested for performance); new benchmarks measuring the parse, validate, and format phases separately and covering cold-start and representative real-world input shapes; a robustness benchmark/test checking the public API survives hostile input.
CI now benchmarks the base commit on the same runner as the PR branch before posting a comparison, and only reports statistically significant changes (finished the following release, v9.0.38's #425).

Changed

Enabled EnablePackageValidation on both packable projects (PhoneNumbers, PhoneNumbers.Extensions).
Restore lock files were committed and checked in CI for reproducible restores (reverted again the next release, v9.0.38, above, once it was clear the complexity wasn't paying for itself).
Centralized build settings into Directory.Build.props and package versions into Directory.Packages.props (Central Package Management) — the structure CLAUDE.md now documents.
Pinned the SDK major version and added a build-reproducibility check; cached NuGet packages in CI.
Dropped the out-of-support net9.0 target framework and the netframework4.8 test target; guarded nullable annotations by TFM name rather than by .NET version.
NuGetAudit findings no longer fail the build outright.

Fixed

The offline geocoder threw instead of returning nothing for a region with no localized name.
A race between parallel inner builds cleaning the generated binary-metadata output.
GetSupportedRegions returned a mutable reference instead of a copy; region sets are now frozen.
Oversized input could overflow the stack buffer in Normalize.
The release tag is now pinned to the commit just pushed, fixing a release-tag-determinism bug.
Exceptions thrown from PhoneNumberUtil now format with invariant culture and name their arguments.

9.0.363 Aug 2026

libphonenumber-csharp 9.0.36 · libphonenumber-csharp.extensions 9.0.36 · upstream v9.0.36

What's Changed

feat: add opt-in java/proto check overrides to the metadata update script by @wmundev in #359
feat: run compatible workflows on ARM64 runners for potentially quicker build times by @wmundev in #360
build(deps): bump actions/setup-dotnet from 5.3.0 to 6.0.0 by @dependabot[bot] in #362
fix: port v9.0.36 upstream java changes by @twcclegg in #363
build(deps): bump github/codeql-action/analyze from 4.36.2 to 4.37.3 by @dependabot[bot] in #361
Bump the phonenumbers_demo_tests_minor_patch_updates group with 2 updates by @dependabot[bot] in #365
build(deps): bump actions/cache/restore from 5.0.5 to 6.1.0 by @dependabot[bot] in #367
build(deps): bump actions/checkout from 7.0.0 to 7.0.1 by @dependabot[bot] in #366
Remove AppVeyor by @twcclegg in #368

Full Changelog: v9.0.35...v9.0.36

Open source →

Additional notes

Changed

Removed AppVeyor entirely — CI is GitHub Actions only from here on (matches CLAUDE.md's "There are no Windows runners").
Compatible workflows now run on ARM64 runners for faster builds.
lib/github-actions-metadata-update.sh gained a --dry-run option, opt-in overrides for the java/proto-file check, hardening for bash 3.2, scoped git identity, and no longer hard-codes the target repository.
The GitHub Release now links back to the published NuGet packages and the upstream libphonenumber release it tracks; publish_nuget.yml is dispatched only after the release tag is created; CI now verifies release packaging directly.
Ported the corresponding upstream Java behavior changes for v9.0.36.

Open source →

9.0.3322 Jun 2026

libphonenumber-csharp 9.0.33 · libphonenumber-csharp.extensions 9.0.33 · upstream v9.0.33

What's Changed

chore: harden GitHub Actions workflows by following security best practices and update some readmes by @wmundev in #352
Security and supply-chain hardening: XXE fix, CI hardening, OpenSSF Scorecard, deterministic builds, and governance docs by @twcclegg in #353

Full Changelog: v9.0.32...v9.0.33

Open source →

Additional notes

Security- and process-hardening release, alongside two metadata-parity fixes.

Added

SECURITY.md, CODE_OF_CONDUCT.md, and CODEOWNERS.
OpenSSF Scorecard workflow (scorecard.yml), running on main and on branch-protection changes.
Deterministic-build verification.

Fixed

Hardened the custom-metadata XML parser (BuildMetadataFromXml, used by the legacy PhoneNumberUtil(Stream) constructor) against XXE (XML External Entity) attacks.
Hardened GitHub Actions workflows following security best practices (least-privilege permissions, pinned actions) and refreshed several READMEs to match.
Ported an upstream v9.0.33 E.164 short-code fix and a previously-missed Mexican (MX) area-code change from v9.0.30 (above).

Open source →

9.0.325 Jun 2026

libphonenumber-csharp 9.0.32 · libphonenumber-csharp.extensions 9.0.32 · upstream v9.0.32

What's Changed

feat: add dotnet 10 support by @wmundev in #328
Performance improvements and more benchmarks by @twcclegg in #347
feat: beautify demo website by @wmundev in #348
build(deps): bump actions/deploy-pages from 4 to 5 by @dependabot[bot] in #350
build(deps): bump github/codeql-action from 4.35.4 to 4.36.0 by @dependabot[bot] in #349
reduce performance tests scope for speed by @twcclegg in #351

Full Changelog: v9.0.31...v9.0.32

Open source →

Additional notes

This release shipped a new target framework, AOT compatibility, and a redesigned demo site.

Added

net10.0 target framework. (#328)
Cold-start benchmarks, in addition to the existing steady-state ones.

Changed

Made the library AOT-compatible (IsAotCompatible, trim/AOT analyzer warnings now build errors on modern TFMs) — the Blazor WASM demo depends on this too.
Beautified the Blazor demo website's UI. (#348)
Reduced the performance-test job's scope for CI speed; restored System.IO.Compression after an earlier removal attempt (v9.0.31, below) needed it back.

Open source →

9.0.3123 May 2026

libphonenumber-csharp 9.0.31 · libphonenumber-csharp.extensions 9.0.31 · upstream v9.0.31

What's Changed

Feature/add performance tests results to pr by @wmundev in #331
feat: run codeql on pr too by @wmundev in #332
fix: fix-performance-test-report by @wmundev in #335
fix: fix performance test comment report by @wmundev in #336
refactor: refactor offline geocoder to use prefixmap similar to java version by @wmundev in #334
feat: add test coverage for DataModelsAndExceptions and BuildPrefixMapFromBin by @wmundev in #337
fix: fix performance test pr comment, just use the output of dotnet benchmark by @wmundev in #338
feat: remove unneeded System.IO.Compression package by @wmundev in #339
feat: embed debug symbols for cross platform by @wmundev in #340
feat: add a demo website deployed to github pages for this library by @wmundev in #342
feat: fix github pages build issue by @wmundev in #343
feat: auto update demo projects in dependabot by @wmundev in #344
build(deps): bump github/codeql-action from 4 to 4.35.4 by @dependabot[bot] in #346
build(deps): bump actions/upload-pages-artifact from 3 to 5 by @dependabot[bot] in #345

Full Changelog: v9.0.30...v9.0.31

Open source →

Additional notes

Added

A Blazor WebAssembly demo site (PhoneNumbers.Demo), deployed to GitHub Pages by deploy-demo.yml — doubles as proof the library works trimmed under WASM. (#342, #343)
Cross-platform embedded debug symbols for both packages. (#340)
Test coverage for DataModelsAndExceptions and BuildPrefixMapFromBin. (#337)
CodeQL now also runs on pull requests, not just on a schedule. (#332)

Changed

Refactored the offline geocoder to use the binary prefix map the same way the Java version does. (#334)
Removed the now-unneeded System.IO.Compression package reference. (#339)
Several fixes to how the performance-test PR comment reports its results. (#335, #336, #338)
Dependabot now also tracks the new demo projects' dependencies. (#344)

Open source →

9.0.307 May 2026

libphonenumber-csharp 9.0.30 · libphonenumber-csharp.extensions 9.0.30 · upstream v9.0.30

What's Changed

docs: convert javadoc to xml by @wmundev in #318
feat: add better performance tests by increasing the dataset to 100000 by @wmundev in #319
feat: add in dependabot config for performance tests by @wmundev in #320
docs: add more timezone tests and update readme for the PhoneNumberToTimeZonesMapper by @wmundev in #321
fix: port behavior fixes from upstream Java libphonenumber by @twcclegg in #322
feat: build metadata as per-region binaries; drop runtime XML/zip parsing by @twcclegg in #323
perf: reduce allocations on Parse / IsValid / Format hot path (#309) by @twcclegg in #324
modern c# by @twcclegg in #326
feat: add missing PhoneNumberToCarrierMapper feature that is available in java version by @wmundev in #317
fix: drop intlFormat when XML value is "NA" instead of emitting literal by @twcclegg in #327
feat: remove old zip commands by @wmundev in #329
perf: enable Compiled regex for dynamic metadata patterns by @twcclegg in #325

Full Changelog: v9.0.29...v9.0.30

Open source →

Additional notes

The architectural turning point behind most of CLAUDE.md's "Singleton + metadata loading" notes: phone metadata moved from parsed XML to binary files generated at build time and embedded in the assembly. (net10.0 landed the release after this one — v9.0.32, above.)

Added

IMetadataLoader + a lazy MetadataSource, with EmbeddedResourceMetadataLoader as the default implementation reading per-region binary files generated at build time by the new PhoneNumbers.MetadataBuilder project.
PhoneNumberToCarrierMapper, matching a feature already present in the Java library. (#317)
Much larger performance-test datasets (100,000 entries instead of the previous size). (#319)

Changed

Metadata pipeline rewrite: BuildMetadataFromXml and the geocoding/timezone text metadata are now converted to per-region binary files at build time (BuildBinaryMetadata, BuildGeocodingBins, BuildTimezoneBin MSBuild targets) and read from embedded, gzip-compressed resources at runtime — XML is no longer parsed on the default load path. PhoneNumberUtil/MetadataManager switched to the new lazy MetadataSource; the old RegexCache-based approach was removed where superseded. Made the multi-TFM build of the binary metadata race-free.
Dropped intlFormat instead of emitting a literal "NA" when the upstream XML value is NA. (#97)

Performance

Enabled compiled regex for dynamic metadata patterns; cached GetOrAdd factory delegates in the metadata and regex caches; shared the national-significant-number string between region lookup and validation instead of recomputing it; skipped a redundant StringBuilder copy in MaybeExtractCountryCode.

Fixed

Ported several additional upstream Java behavior fixes as part of the metadata-pipeline work.

Open source →

9.0.1018 Jul 2025

20 releases. Upstream metadata syncs, several bundled only a mechanical LocaleData.cs regeneration, plus routine Dependabot CI bumps (codecov-action,

20 releases. Upstream metadata syncs, several bundled only a mechanical LocaleData.cs regeneration, plus routine Dependabot CI bumps (codecov-action, actions/checkout, actions/setup-dotnet, github/codeql-action) and NuGet test-project dependency groups. No changes to the library's own source.

Open source →