Free online developer tools — JSON formatter, image compressor, Base64/URL encoders, JWT decoder, UUID and password generators, and 50+ more. No signup required, everything runs in your browser. Also includes 50 troubleshooting guides for real errors developers hit (JSON parsing, Docker, AI-API rate limits), 20 language cheatsheets, and 13 tech comparisons. Built because free dev-tool sites shouldn't bury the actual tool under a signup wall.