DevJSON — JSON API Inspector

About

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)