DevJSON — JSON API Inspector

Intercept, format, search, diff, and export JSON API responses in DevTools

DevJSON adds a dedicated panel to Chrome DevTools for inspecting JSON API responses. Open DevTools, click the DevJSON tab, and every JSON response is automatically captured, formatted, and browsable. Why DevJSON? Built as a modern alternative to JSON Viewer Pro (unmaintained since 2023). Zero permissions, no data collection, and packed with features the competition lacks. CORE FEATURES - Auto-capture all JSON responses (9 MIME types including NDJSON) - Collapsible JSON tree with syntax coloring and auto-expand - Search across keys and values with match highlighting - Next/prev navigation through search results - One-click copy of formatted JSON - Request/response header inspection POWER FEATURES - JSON diff — compare two responses side by side with color-coded changes - JSONPath queries — filter with expressions like $.data[*].name, with match highlighting and navigation - Request timing waterfall — mini color bar per request, detailed phase breakdown (blocked, DNS, connect, SSL, send, wait, receive) - Pin/bookmark — pin important requests to the top, pinned items survive clear - BigInt precision — large integers (Snowflake IDs, financial APIs) displayed without JS float loss - Paste/import JSON from clipboard or file - Export filtered requests as JSON or HAR 1.2 with real timing data - JSON Lines (NDJSON) format support with auto-detection - Chunked rendering for 10k+ node responses without lag DEVELOPER UX - Keyboard navigation: j/k to browse, / to search, n/N for matches, p for JSONPath, b to pin, ? for help - 4 syntax themes: Dark, Light, Monokai, Solarized - Resizable split panes - JSON path display — hover any node to see its path, click to copy - Expand/collapse all toggle - URL filter for the request list PRIVACY FIRST - Zero permissions — no host access, no tabs, no storage permissions - No background scripts, no content scripts - No analytics, no tracking, no network requests - Lightweight: ~42KB total JavaScript bundle (Preact, not React)