Small tools for developers
abcdef.lol
Free browser-based developer utilities for formatting JSON, decoding JWTs, converting Unix time, generating UUIDs, passwords, API keys, hashes, testing regex, visualizing cron, and previewing Markdown.
> open abcdef.lol ready: json jwt time uuid password api-key base64 hash url regex cron markdown privacy: local-first latency: tiny
Tools
No login, no server round trips for your input, no theater.
JSON Formatter
Format, minify, and validate JSON in your browser.
JWT Encoder / Decoder
Decode JWTs or create unsigned JWTs from header and payload JSON.
Unix Timestamp Converter
Convert Unix timestamps to local and UTC dates.
UUID Generator
Generate one or many UUID v4 values locally.
Password Generator
Generate strong random passwords with local browser crypto.
API Key Generator
Generate random API keys with prefixes, lengths, and safe alphabets.
Base64 / atob / btoa
Encode, decode, and test raw atob() / btoa() behavior in the browser.
Hash Generator
Generate SHA-256, SHA-512, and MD5 hashes from text input.
URL Encoder / Decoder
Encode and decode URL components with clear error handling.
Regex Tester
Test regular expressions and get a local plain-English explanation.
Cron Visualizer
Validate 5-field cron expressions and preview upcoming runs.
Markdown Playground
Write Markdown and preview sanitized rendered HTML live.