Originally published on DevToolsHub — a collection of free, privacy-first online developer tools. All processing is done locally in your browser.
Every developer has a toolkit — but the best tools are the ones that are always accessible, never ask for a credit card, and keep your data private. In 2026, the bar for "good enough" online tools has risen dramatically. Here are 10 free online developer tools that deliver real power without the bloat.
1. JSON Formatter & Validator
Working with APIs means working with JSON — lots of it. A good JSON formatter does more than just pretty-print. The DevToolsHub JSON Formatter validates your structure, highlights syntax errors, and lets you toggle between compressed and formatted views.
Whether you are debugging a REST API response or writing a config file, this is the first tool you should bookmark.
