regex101

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Score6.9

Rank#2 of 23

From€4.99/mo

Free planYes

Free trialYes

Runs onAPI, Linux, Self-hosted, Web

Summary

regex101 is an online tool for building, testing, and debugging regular expressions. Its editor supports PCRE2, JavaScript, Python, Golang, Java, .NET 10.0, Rust, POSIX ERE, POSIX BRE, and legacy PCRE. Explanations show how each part of a pattern matches according to the selected flavor, and users can step through matching. Results can be exported as JSON, JSON Lines, CSV, or plain text. Developer options include HTTP APIs, an MCP server, editor links, and a separately licensed parser package. The workspace API stores editor data but does not offer a remote matching endpoint. File loaders process text, bytes, and supported documents locally in the browser; saving or sharing workspace input can send it to the workspace service. The free plan includes core tools, one test string, and saved workspaces with an account. Pro costs 4.99 EUR per month, billed yearly, and adds multiple test strings, substitution pipelines, benchmarking, formatting, and an ad-free workspace. A self-hosted Enterprise option is also listed, with a Linux, Docker Compose, MySQL, and Redis setup documented.

Who it is for

regex101 suits people who need to build or debug patterns across several regex flavors and want explanations of match behaviour. Pro is relevant to users needing multiple test strings or the additional listed tools; Enterprise is an option for self-hosting.

What is good

Supports ten listed regex flavors.
Explains matches according to the selected flavor.
Exports results in four formats.
Free plan includes core tools and saved workspaces.
Offers self-hosted Enterprise deployment.

What to know first

Free plan includes only one test string.
Pro costs 4.99 EUR per month, billed yearly.
Workspace API does not provide remote matching.

Verdict

regex101 combines pattern editing, flavor-specific explanations, step-through debugging, and result export. The free plan is limited to one test string, while Pro adds multiple strings and other listed tools for 4.99 EUR per month billed yearly.

regex101 plans and pricing

All plans

Free Free Core regex tools · one test string · saved workspaces with an account regex101.com · 30 Sept 2026

Pro €4.99/mo billed yearly Multiple test strings · substitution pipelines · advanced benchmarking · regex formatting · ad-free workspace regex101.com · 30 Sept 2026

Enterprise Not published Annual license; invoice-based billing Self-hosted · one running instance per standard license · user count specified on invoice · optional feature add-ons docs.regex101.com · 30 Sept 2026

Compared on regular expression testers

Free plan: Yesregex101.com
Regex flavors: PCRE2 (PHP), JavaScript, Python, Golang, Java, .NET, Rust, POSIX ERE, POSIX BRE, PCRE (Legacy)regex101.com
Pattern explanation: Yesregex101.com
Step-through debugger: Yesregex101.com
Code generation: Yesregex101.com
Saved patterns: Yesregex101.com

Facts

Purpose: regex101 is an online tool for building, testing, and debugging regular expressions.regex101.com · 30 Sept 2026
Explanations: The site explains each part of a regular expression and how it matches, tailored to the selected flavor.regex101.com · 30 Sept 2026
Match exports: Match results can be exported as JSON, JSON Lines, CSV, or plain text.regex101.com · 30 Sept 2026
Developer integrations: Developer integrations include HTTP APIs, an MCP server, editor links, and a separately licensed parser package.docs.regex101.com · 30 Sept 2026
API limitation: The workspace API stores editor data and does not expose a remote matching endpoint.docs.regex101.com · 30 Sept 2026
File privacy: File loaders read text, bytes, and supported documents locally in the browser; saving or sharing the resulting workspace input can send it to the workspace service.docs.regex101.com · 30 Sept 2026
Enterprise data handling: For self-hosted Enterprise, patterns, test strings, workspaces, and files are processed in the customer deployment, which regex101 ApS says it does not access.docs.regex101.com · 30 Sept 2026
Enterprise deployment: The documented standard setup runs on Linux with Docker Compose and uses MySQL and Redis services.docs.regex101.com · 30 Sept 2026
Support: Support includes community discussion, a public issue tracker for reproducible bugs, and email for account, purchase, or private support.docs.regex101.com · 30 Sept 2026
Enterprise support terms: The Enterprise agreement states a reasonable-effort initial response target of five Danish business days and says it is not a guaranteed SLA.docs.regex101.com · 30 Sept 2026
Maker: The maker is regex101 ApS; its terms list an address at Mimers Plads 2, 6. tv, 2220 Copenhagen.docs.regex101.com · 30 Sept 2026