# Reference implementations and sources
Inspection date: 2026-07-27.
| Reference | Exact revision/version | Licence | Use and copying status |
| -------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------- |
| Regex Tools | Release identity `v0.4.0` | GPL-3.0-or-later | Application source written for this project. |
| Toolbox SDK | `53c40a61ba1581246f65773fcbb1c1cfd31ac98e` / 0.2.2 | Apache-2.0 | Contract, shell and release conventions; package APIs used, no source adapted. |
| Toolbox Portal | `9347554324299c8ec9dfaec2c9730907736f62c3` / aggregate v0.8.0 / package 0.2.7 | AGPL-3.0-only | Assembly/lock conventions inspected; no source copied into the app. |
| regexpp | 4.12.2; pinned npm integrity in `package-lock.json` | MIT | ECMAScript 2025 syntax provider; normalized in the syntax worker. |
| PCRE2 | Signed tag 10.47; commit `f454e231fe5006dd7ff8f4693fd2b8eb94333429` | BSD-3-Clause WITH PCRE2-exception | Standalone pinned offline build; verified 8-bit WebAssembly pack shipped, source not vendored. |
| PHP | Executable identity 8.5.8; embedded PCRE2 identity 10.44 | PHP License version 4 (BSD-3-Clause), elected through the earlier licence's later-version option | Actual PHP `preg_*` compiler, matcher and replacement runtime; PHP source not vendored. |
| WordPress Playground `@php-wasm` | `web-8-5`, `universal`, `util`, `logger`, `stream-compression` and `progress` 3.1.46; pinned npm integrities | GPL-2.0-or-later | Self-hosted PHP WebAssembly distribution/host packages; their separate GPL notice is included and recorded in the pack metadata. |
| WebPerl | 0.09-beta; commit `6f2173d29a2c2e3536e1de75ff5d291ae96ab348`; prebuilt archive SHA-256 `5f441249217e90ab378c666f473d4206ab4f44907f6bb0aa8d70834bc38c40dc` | GPL-1.0-or-later OR Artistic-1.0-Perl | Unmodified legacy prebuilt pack containing Perl 5.28.1; visibly labelled beta/legacy. |
| Emscripten used by WebPerl | 1.38.28 | MIT OR NCSA | Upstream-generated legacy Perl loader/runtime; applicable licence included. |
| Pyodide | Tag 314.0.3; commit `ac57031be7564f864d061cb37c5c152e59f83ad4`; pinned npm integrity | MPL-2.0 | Reviewed self-hosted runtime pack; no CDN use. |
| CPython | Executable runtime identity 3.14.2 in Pyodide 314.0.3 | PSF-2.0 | Actual `re` compiler, matcher and replacement runtime; Python source not vendored. |
| ruby.wasm / CRuby | `@ruby/4.0-wasm-wasi` and `@ruby/wasm-wasi` 2.9.3-2.9.4; executable CRuby identity 4.0.0 | MIT for ruby.wasm host; Ruby/BSD and component terms in bundled NOTICE | Minimal self-hosted CRuby `Regexp` runtime; pinned npm integrities/notices; fixed file/JSON bridge avoids the JavaScript-eval conversion. |
| TeaVM | Tag/commit `ee91b03e616c4b45401cd11fb0cd7eb0daf6649b` / 0.15.0 | Apache-2.0 | `java.util.regex` class library compiled into the verified Java module; not OpenJDK. Also backs the explicit Scala compatibility profile. |
| Emscripten / libc++ | Emscripten 6.0.4 compiler revision `fe5be6afdff43ad58860d821fcc8572a23f92d19` | MIT OR NCSA; Apache-2.0 WITH LLVM-exception | Compiles the application C++ bridge against libc++ `std::wregex`; toolchain source not vendored. |
| Go | Tag 1.26.5; commit `c19862e5f8415b4f24b189d065ed739517c548ba`; official archive SHA-256 `5c2c3b16caefa1d968a94c1daca04a7ca301a496d9b086e17ad77bb81393f053` | BSD-3-Clause | Standard-library `regexp` compiler/matcher and official `js/wasm` runtime. |
| Rust `regex` | 1.13.1; commit `2b527599eb9eea0dcc288c704584f242f26a5c61`; crate checksum `f020237b6c8eed93db2e2cb53c00c60a8e1bc73da7d073199a1180401450218d` | MIT OR Apache-2.0 | Actual crate compiler/matcher built for WebAssembly with the pinned Cargo graph. |
| Rust toolchain | rustc 1.97.1 commit `8bab26f4f68e0e26f0bb7960be334d5b520ea452`; wasm-bindgen 0.2.126 | Apache-2.0 OR MIT plus bundled component terms | Exact compiler, standard library and binding tool identities recorded in pack metadata. |
| .NET | SDK 10.0.302 / runtime 10.0.10; runtime commit `f7d90799ce` | MIT plus bundled third-party notices | Actual `System.Text.RegularExpressions` browser-WASM runtime. |
| ECMAScript specification | ; living specification inspected 2026-07-24 | ECMA terms | Semantics reference; no prose copied. |
| regex101 | and public parser documentation | Product/commercial terms | Product reference only. No source, branding, explanations, reference prose or visual design copied. |
| `recheck` | 4.5.0 | MIT | Metadata inspected; not installed or shipped. |
| `regexp-ast-analysis` | 0.7.1 | MIT | Metadata inspected; not installed or shipped. |
| RegexHub | Repository revision `d1d9f19d259745dfdd21935b9ef3e747b62b9bfb` | MIT | Potential future adversarial cases; no file copied. |
| RegexLib | Website inspected | Redistribution licence not established | No fixture copied. |
| RGXP.RU | Website inspected | Redistribution licence not established | No fixture copied. |
All v0.1.0 through v0.4.0 conformance cases are project-authored. See
`tests/fixtures/README.md`. Runtime pack metadata and adjacent licence/notice
files are authoritative for the exact binary distribution.