Mock Data Generator - Paste real JSON, get 1,000 coherent rows that match it

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.

Hey Product Hunt 👋 I build developer tools at jsondevtools.org, and mock data generators kept frustrating me for two reasons: most cap your rows or want a signup, and the ones that don't still generate junk — a row where the name is "Alice Smith" but the email is "qz8@example.com" and the city, state, and ZIP belong to three different places. So I built one that fixes the second problem, not just the first. What's different: 🧩 Paste a real JSON sample → get more like it. Drop in one object or an array, and it infers a generator per field, then produces as many lookalike rows as you want. Fastest path from "here's my shape" to "here's 5,000 rows of it." 🔗 Coherent rows. Email and username derive from that row's name. City/state/ZIP come from one real location. updatedAt is never before createdAt. The values in a row actually make sense together. 🎲 Seeded & deterministic. Type anything into the seed box and the same schema produces byte-identical output every run — great for snapshot tests and shareable fixtures. 🔒 100% in your browser. Your schema and sample never leave your device. Works offline. No row cap, no signup. Three ways in: a field-picker schema builder, paste-a-sample inference, or a JSON Schema. Export JSON, NDJSON, or CSV. It's free and I'm actively building v2 (SQL export, relational/linked entities with real foreign-key coherence). Would genuinely love feedback on what'd make this part of your actual workflow — reply here and I'll read every comment.

Mock Data Generator - Paste real JSON, get 1,000 coherent rows that match it

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