Regex Builder: English description → working regex + test matches
Describe what you want to match in plain English, get a regex, an explanation, and real matched substrings from your test strings. Powered by Claude, swap to free Llama 3.1 in 4 lines.
Stack: Node.js / Next.js·OSS difficulty: easy·Email to download
Free download
Regex Builder
Freeemail required
Working code + OSS-swap guide + sample inputs and outputs. Same delivery as the paid wrappers — just $0.
Try it now
Live demo, in your browser.
Test the wrapper before you download. The free demo routes through qwen2.5:3b on our VPS (free, slower). Want to test with your own Claude, OpenAI, or Ollama URL? Use the bring-your-own-model panel below the demo. The download lets you swap providers freely.
Output will appear here after you run the demo.
What is in the ZIP
Code, guide, samples. Enough to ship in 30 minutes.
→Node 20 + Express server, POST /api/build returns pattern plus real matches
→Server compiles the regex and re-runs it against your test strings, so matches are ground truth not model guesses
→Strict JSON contract with markdown-fence-tolerant parser and compile-error surface
→Vanilla HTML/JS frontend, dark theme, no build step
→Ships with 3 sample descriptions (phone, .edu email, ISO date) plus expected matches
→Swap-in guide: Claude Haiku 4.5 to Ollama Llama 3.1 8B in 4 env-var lines
→Layman-language guide on the OSS swap (no jargon, no assumed expertise)
→README with copy-paste setup commands
→Sample inputs and reference outputs
Adding it takes about 30 minutes
1
Enter your email.
Free wrapper. Email confirms the download link, no account.
2
Download the ZIP.
Working Node.js app, README, sample inputs, reference outputs, the OSS-swap guide.
3
Run it locally in 30 minutes.
Follow the README. Ships with the Claude path wired. Swap to Llama whenever you want free.
Common questions
When do I actually get the code?
Instantly. Submit your email, download link arrives in about 30 seconds. Same link serves the latest version forever.
Do I need to know AI/ML to use this?
No. The wrapper is a working app you can deploy in 30 minutes following the README. The OSS-swap guide is written for developers who know JavaScript or Python but have never touched a model file.
What does free open-source model actually mean here?
Llama 3.1 8B via Ollama is a model (or set of models) you can run on your own hardware with no API keys, no per-call billing, and no rate limits beyond what your CPU or GPU allows. The guide walks the install, config, and swap end to end.
Lifetime updates?
Yes. When v1.1 ships with new features or OSS-model paths, the same unlock link serves the latest version.