JavaScript Regex Tester
Extract order IDs, verify SKUs, or test a new regular expression without sending the sample text to a server.
Open free tool ↗Free · Optional ads · No account
Small dev tasks.
Solved locally.
Eight original utilities for the tasks that interrupt a coding session: regex matching, cron schedules, timestamps, token structure, encoding and NDJSON. Everything runs on your device.
Choose a tool ↓8 working utilities
No input sent off-device
Original open source
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What do you need to do?
8 TOOLS5-Field Cron Schedule Preview
Check whether a server job will run on Monday at 09:00 UTC or local time before you put it into production.
Open free tool ↗Unix Timestamp Converter
Paste a 10-digit epoch in seconds or a 13-digit millisecond timestamp and see the same moment across time zones.
Open free tool ↗JWT Header & Payload Decoder
Inspect the JSON inside a disposable JSON Web Token without sending it to a server or pretending its signature is valid.
Open free tool ↗UTF-8 Base64 Encoder & Decoder
Encode non-ASCII JSON text for a test payload or decode a Base64 string without losing Korean or emoji characters.
Open free tool ↗URL Encoder, Decoder & Query Inspector
Check exactly what an API parameter or marketing UTM query string contains without opening that link.
Open free tool ↗UUID v4 Generator
Need safe unique-looking IDs for fixtures, migration samples or request correlation without a server round trip?
Open free tool ↗JSONL / NDJSON Validator
Validate OpenAI batch requests, n8n logs or NDJSON streams before they enter a data pipeline.
Open free tool ↗Why browser-local?
Text, JWT examples, regex samples and JSONL records are processed locally. No analytics; ads load only on this information page after explicit consent. Tool workspaces remain ad-free. Avoid pasting live passwords and bearer tokens into websites, even privacy-conscious ones.
These are original implementations of common developer workflows—not copies of another site's code or interface. A useful new page does not guarantee Google search ranking or visitors.