A free, privacy-first mock data generator for developers that creates coherent, reproducible datasets. Generate data using a field picker, a pasted JSON sample, or JSON Schema. Emails, locations, and timestamps stay logically consistent. Use a seed for identical output every time. Export unlimited JSON, NDJSON, or CSV. Runs entirely client-side, works offline, and requires no signup.

Free, no-signup HTTP status code quiz for early-career devs and CS students. 10 mixed questions per round, easy to trivia difficulty ramp, streaks, and a shareable rank. Practice 401 vs 403, 404 vs 410, 429 vs 503, and the codes that come up in every interview.

Hey hunters 👋 I'm Pasindu, the maker. Most JSON Schema generators use one sample and assume every field is required and every type fixed — almost never true for real APIs. Paste 2–5 real samples and this merges them: missing fields become optional, mixed types become nullable unions. A schema that matches reality, not one lucky response. 100% client-side, no signup, free. Part of jsondevtools.org. Feedback on the merge logic welcome — what JSON pain should I solve next?

JSON → TOON Converter transforms JSON into TOON (Token-Oriented Object Notation), a compact format designed for LLM workflows. It reduces token usage by removing JSON verbosity like repeated keys and brackets. Use it to optimize prompts, AI agents, RAG payloads, and API calls. Runs fully in browser with no signup or backend.

JSONDevTools.org is a complete toolkit for developers who care about privacy and speed. No sign-up. No data collection. All processing happens in your browser — your data is never sent to a server. Includes: Formatter, Validator, Diff, Viewer, JWT Decoder, and more. Perfect for debugging APIs, fixing JSON errors, and daily development work.