All developer tools
Everything here runs in your browser. Pick a tool and start typing — there is no upload step, no processing queue and no account.
Text tools
Tools for matching, extracting and transforming text — including a regex tester that explains what your pattern actually does, in plain English.
Time and scheduling tools
Tools for scheduling and time expressions — build cron expressions visually, read existing ones in plain English, and preview exactly when they will next run.
Data format tools
Tools for working with structured data — format and validate JSON with precise error locations, explore it as a tree, and convert between JSON and YAML.
Reference and guides
Longer-form pages for when the tool has answered your question and raised two more.
- Regex Cheat Sheet
Every regex token with a worked example, plus where the major languages disagree.
- Cron Cheat Sheet
Field order, special characters, dialect differences and a table of common schedules.
- How to run a cron job every 5 minutes
The correct expression, the common mistake that silently drifts, and every dialect variant.
- Cron syntax compared: standard, Quartz, node-cron and EventBridge
Field counts, day-of-week numbering and special characters, and why a copied expression can silently run at the wrong time.
- Regex for email addresses in JavaScript
A pattern worth using, what it deliberately misses, and why chasing RFC 5322 is the wrong goal.
- How to fix JSON parse errors
Each parser message translated into the actual problem, with the fix.