regex101

Input—per 1M tokens

Output—per 1M tokens

Context—tokens

WeightsClosed

About

regex101 is ranked #1 of 23 in regular expression testers on Inferse. It runs on API, Linux, Self-hosted, Web. There is a free plan. A free trial is offered. Paid plans start at €4.99/mo.

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
Regex flavors: The editor lists PCRE2, JavaScript, Python, Golang, Java, .NET 10.0, Rust, POSIX ERE, POSIX BRE, and legacy PCRE support.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