A JSON viewer and analysis toolkit built for files that crash everything else
Native Rust + SIMD engine. Multi-GB JSON, HAR analysis, API client, SQL export — all offline, all on your Android device.
Rust + SIMD Core · No Cloud · No Account · Read-Only & Safe
A native Rust core with SIMD acceleration handles what JavaScript-based viewers simply cannot. Tested with files over 100 GB.
- Rust + SIMD Core — Native code, not a JavaScript wrapper. SIMD acceleration for search and parsing on ARM64 devices.
- Smart Indexing — First load builds a persistent index. Every subsequent open is near-instant.
- Memory Safe — Streaming architecture prevents Out-Of-Memory crashes on any Android device, regardless of file size.
- Private by Design — Everything runs locally. No cloud, no tracking, no account required.
| Format | Details |
|---|---|
| JSON | Standard, minified, and large-value JSON files |
| NDJSON / JSONL | Line-delimited datasets and event logs |
| CBOR | Binary — automatically transcoded to JSON on first open |
| MessagePack | Binary — automatically transcoded to JSON on first open |
| HAR | HTTP Archive files from Chrome DevTools, Firefox, etc. |
| Markdown | .md file rendering with full formatting |
Interactive hierarchical view for navigating deeply nested JSON structures. Stream through gigabytes like a feed.
- Infinite Scrolling — navigate arrays with millions of items
- Bookmarks — save deep paths to revisit later
- Hidden Paths — collapse irrelevant fields to focus on what matters
- Breadcrumbs — track your exact location in the hierarchy
- Jump to Path/Index — JSONPath syntax or direct array index
- Base64 Detection — 40+ formats auto-detected, preview images inline, extract decoded files
Bird's-eye view of your JSON schema — visualize the shape of unfamiliar data without reading it line by line.
- Interactive Graph — zoomable, pannable tree diagram
- Schema Export — TypeScript interfaces or JSON Schema Draft-07
- Visual Export — save the structure graph as PNG
High-performance raw text viewer for log analysis and deep search operations.
- Advanced Search — regex or standard with scrollable match navigation
- Occurrence Counter — count matches across the entire file
- Persistent Highlights — mark terms and track them as you scroll
- GenAI Regex Helper — describe your search in plain English, AI generates the regex
Drop a .har file exported from Chrome DevTools, Firefox, or any proxy tool and get an instant breakdown.
- Overview Dashboard — total requests, transfer size, avg response time, error count
- Timing Waterfall — DNS, connect, SSL, wait, receive breakdown per request
- Per-Request Detail — headers, cookies, request/response body with syntax highlighting, timing, TLS info
- Filter & Search — by method, status code, content type, domain, or response time
- Clone to API Client — replay any HAR request in the built-in API client
REST & GraphQL client built for mobile. Not a full Postman replacement, but covers most real-world workflows.
- HTTP Methods — GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS, and GraphQL with variable support
- Authentication — Basic, Bearer Token, OAuth 2.0 with PKCE, AWS Signature V4
- Postman Collection Import — v2.0 and v2.1 with folder structure and inherited auth
- cURL Import & Export — paste from DevTools, export to share
- Environments & Variables —
{{variable}}syntax with Postman-compatible precedence - Network Metrics — DNS, TCP, TLS, TTFB, and download timing per request
- File Attachments — multipart uploads, binary body payloads, session cookies
- Visual Query Builder — build multi-condition filters with AND/OR logic and parentheses grouping, no code required
- GenAI Regex Builder — describe what you want in plain English, on-device AI generates the pattern
- SQL & CSV Export — convert JSON to database-ready SQL (MySQL, PostgreSQL, SQLite, SQL Server, Oracle, MariaDB) or CSV
- Data Masking — redact sensitive fields during export for safe sharing
- Schema Validation — validate against JSON Schema Draft-07
- Local Receive — transfer files from desktop via WiFi drag-and-drop, no cables or cloud needed
- Mock API Server — turn your phone into a mock server with custom endpoints and a web dashboard
- Unescape & Prettify — fix double-escaped JSON and beautify minified content in one tap
- Bookmarks — save exact positions deep inside large files, even in multi-GB NDJSON streams
- Base64 Detection — 40+ formats auto-detected, preview images inline, extract decoded files
GiantJSON hosts developer tools locally on your phone. Open a browser on any device on the same network and use them. Nothing is sent to the internet.
- File Transfer — drag-and-drop or CLI (curl, PowerShell, Python)
- JWT Decoder — decode header, payload, signature with expiry status
- Timestamp Converter — epoch to UTC, local, ISO 8601, auto-format detection
- JSON Formatter — format, minify, stringify, or unescape
- URL Encoder / Decoder — encode, decode, and parse URL components
GiantJSON is a one-person project — built and maintained by a solo indie developer. It started as a tool to solve a problem no other app handled well, and evolved into a full developer toolkit.
If it's useful to you, a review on Google Play helps more than you'd think. And if something isn't working right, in-app feedback goes straight to me.
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