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.