I built a JSON toolkit that never sends your data anywhere

Most "paste your JSON here" tools online send that JSON to a server to process it. For internal API responses, config files, or anything with real data in it, that's not something I wanted to do — so I built JSONLinter , a JSON toolkit where literally everything happens client-side. What it does It started as a validator/formatter, then grew into 42 tools across six categories: Validate & Format — validation with precise error locations, pretty print, minify, JSON repair (fixes trailing commas, single quotes, unquoted keys, truncated JSON, etc.) View & Query — tree view, JSONPath queries, structural diff (key order doesn't matter), full-text search Data Converters — CSV, Excel, YAML, XML, SQL, Markdown, both directions Code Generators — infers a type model from a JSON sample and generates TypeScript, Python, Java, C#, Go, Kotlin, Swift, Rust, or PHP Schema Tools — JSON Schema validation + generation Encoding Tools — Base64, escape/unescape, JWT decode There's also an optional AI assistant on the validator page — it's bring-your-own-key (OpenAI or Anthropic), and since there's no backend at all, the key and your JSON go straight from your browser to the provider. I never see either. How it's built Stack is React 19 + TypeScript + Vite, Tailwind v4 for styling, CodeMirror 6 for the editor. A few things I had to solve that were more interesting than expected: Prerendering without SSR. I didn't want to take on a Next.js-style server just to get real HTML for crawlers. Instead, the build runs a headless Chromium pass (Playwright) over every route after vite build and saves the fully-rendered output to dist/<route>/index.html . Crawlers get real content and correct per-page meta tags on first paint; once JS loads, React takes over exactly like a normal SPA. No server, no hydration mismatches to worry about. Structural JSON diff. A text diff on two JSON documents is mostly useless because key order doesn't matter semantically. The diff tool parses both sides and compares t