Free Developer Tools

Utilities for everyday development. No signup, no tracking — and every tool but the AI explainer runs entirely in your browser.

AI Debugging

Explain This Error (AI)

Paste an error or stack trace and get a plain-English explanation, the likely cause, and how to fix it.

Explain This Regex (AI)

Paste a regular expression and get a plain-English explanation, a token-by-token breakdown, and example matches.

Formatters & Parsers

JSON Formatter & Validator

Format, validate, and beautify JSON data instantly. Catch syntax errors with line numbers.

Stack Trace Parser

Paste a raw stack trace and get it parsed into structured frames with file, line, and function info.

Regex Tester

Test regular expressions with live match highlighting, capture groups, and flag controls.

Encoders & Decoders

Base64 Encode / Decode

Encode text to Base64 or decode Base64 strings back to plain text. Supports UTF-8.

Epoch / Unix Timestamp Converter

Convert between Unix timestamps and human-readable dates. Supports seconds and milliseconds.

JWT Decoder

Decode and inspect JSON Web Tokens. View header, payload, and expiration status.

Generators

UUID Generator

Generate random v4 UUIDs instantly. Bulk generation up to 100 at a time with one-click copy.

Cron Expression Generator

Build cron expressions visually and preview the next scheduled run times.

Reference Guides

HTTP Status Code Reference

Searchable reference of all HTTP status codes with descriptions, common causes, and debugging tips.

Log Levels Reference

Interactive reference mapping log levels across Python, Java, Node.js, Go, and syslog.

Frequently Asked Questions

Are these tools really free?

Yes — every tool is free with no signup and no ads. The AI tools (Explain This Error and Explain This Regex) have a fair-use rate limit so they stay available; the rest are unlimited.

Is my data safe?

Every tool except the two AI explainers runs entirely in your browser — nothing is sent to a server. The AI explainers send the text you paste to the AI model to analyze it, so strip out secrets and personal data first.

Who built these tools?

These tools are built by Bugsly, an AI-powered error tracking platform. We built them because we use them every day.