Giant JSON Viewer: HAR & API

A JSON viewer and analysis toolkit built for files that crash everything else. Supports: json jsonl ndjson har CBOR MsgPack md Made for developers, analysts, and QA engineers who work with massive datasets -- multi-GB logs, database dumps, API responses -- directly on Android. No ads, No cloud, no account, no limits*. While most viewers struggle above 50MB, GiantJSON Viewer uses a native Rust engine to handle multi-gigabyte files without running out of memory. Built and maintained by a solo indie developer. BUILT FOR PERFORMANCE • Large JSON Support: Open files that other viewers can't handle • SIMD accelerated Indexing: First load builds an index for instant navigation • Memory Safe: Designed to prevent Out-Of-Memory crashes on any device • Rust + SIMD Core: Native speed, not a JavaScript wrapper DEVELOPER TOOLKIT • SQL & CSV Export: Convert to SQL queries or CSV tables • Data Masking: Redact selected fields during export • Advanced Filter: Visual query builder with field-level conditions • Search & Regex: Full-text search / filter with regex support • GenAI Regex Builder: Describe what you need, AI writes the regex • JSON Path Navigation: Jump directly to any node • Schema Export: Export structure as JSON Schema, TypeScript, or Markdown • Auto-prettify and syntax highlight in RAW text mode with tree mode collapse feature API CLIENT REST and GraphQL client, right on your phone: • GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS + GraphQL queries • Auth: Basic, Bearer, OAuth 2.0 (with PKCE), AWS Signature V4 • Postman collection import with folder structure and variables • Environment support with variable precedence • File attachments, binary uploads, session cookies • Import/export via cURL • Responses open directly in the viewer HAR ANALYZER Drop a .har file and get a full network analysis dashboard: • Overview stats: request count, response times, errors, transfer size • Timing breakdown, status distribution, domain summary • Filter by method, status, content type, domain, or response time • Request detail tabs: headers, cookies, body, timing waterfall, TLS • Clone any request to API Client or copy as cURL BASIC MOCK API SERVER Turn your phone into a (basic) mock API server JSON DIFF - COMPARE FILES • Structural compare of two JSON / NDJSON files -- formatting and key order never count • Detects moved and renamed data; repeated changes grouped into patterns • Multi-GB tested; match list items by id; Markdown / NDJSON report export 3 VIEW MODES • TEXT: Raw view with syntax highlighting, formatting and collapsible tree • BROWSER: Stream through gigabytes like a folder structure • STRUCTURE: Visualize data structure as a graph to understand its shape HOSTED WEB TOOLS - a private toolset on your local network • File Transfer -- drag and drop files, no cables, no cloud, no size limit • JWT Decoder -- decode tokens, inspect header and payload, check expiry • Timestamp Converter -- epoch to human-readable and back • JSON Formatter -- format, minify, stringify, unescape • URL Encoder -- encode, decode, and parse URLs with query breakdown MORE • Markdown Viewer: Render .md files • Bookmarks: Save locations in huge files to find later in Browser Mode • Hide Paths: hide irrelevant elements from view • Unescape & Prettify: Fix serialized or minified JSON • JSON Schema Validator: Validate against a schema file with detailed error report PRIVATE & SECURE Everything runs locally on your device. • No cloud uploads, no account registration • GenAI Regex only calls AI to generate patterns -- your data never leaves • (!) Anonymous crash reports and usage statistics collected for development (can opt out) This app is a one-person project under active development. If you find it useful, a review on Google Play helps more than you'd think. *Theoretical limits are 1TB, 255 depth, storage space, and some RAM requirement. ~100GB tested