JSON Formatter, Validator & Prettifier
Format, minify, and validate JSON data with lossless 64-bit precision and JSON Schema (Draft-07 / 2020-12) rules.
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Dev Hub · Zero Telemetry & In-Browser Execution
Developer Tools & Code Utilities Hub
High-performance engineering utilities running 100% inside your browser JavaScript runtime. Format complex JSON payloads without truncating 64-bit integers, test regular expressions with ReDoS timeout protection, decode JWTs, build natural language crons, and sanitize environment files — keeping proprietary schemas and API keys completely isolated from network endpoints.
Tools Grouped by User Purpose & Intent
Showing all tools in this category (33)
JSON Formatting, Conversion & Data Structuring
Format, validate, query, and convert structured data payloads.
JSON to CSV & CSV to JSON Converter
Convert tabular data between JSON array structures and CSV spreadsheets bi-directionally.
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JSON to TypeScript Interface Generator
Convert raw JSON payloads into clean, strongly typed TypeScript interface models.
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Excel to JSON & CSV Spreadsheet Converter
Convert .xlsx and .xls workbooks into clean JSON structures and CSV files offline.
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cURL Command to Code Converter
Convert raw cURL shell commands into native Python, JavaScript fetch, and Go code.
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SQL Query Formatter & Beautifier
Beautify complex SQL queries across PostgreSQL, MySQL, and standard ANSI dialects.
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OpenAPI & Swagger Document Inspector
Inspect, parse, and explore OpenAPI 3.1, 3.0, and Swagger 2.0 definitions in JSON/YAML. 100% offline with zero server transmission.
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Regular Expressions, Cron Scheduling & Automation
Build regex expressions, inspect execution patterns, and formulate cron tasks.
RegEx Tester & Real-Time Debugger
Test regular expressions with real-time match highlighting and capture group breakdown.
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Visual RegEx Pattern Builder
Construct complex regular expressions visually without memorizing arcane syntax rules.
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Cron Expression Explainer & Schedule Translator
Translate 5-part crontab expressions into plain, human-readable English sentences.
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Plain English to Cron Expression Generator
Convert natural language scheduling requests into valid 5-part crontab expressions.
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Cron Execution Schedule & Next Runs Calculator
Calculate the next upcoming execution dates and timestamps for any cron expression.
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Authentication, Tokens, Encryption & Environment Config
Decode JWTs, execute client-side crypto, sanitize PII, and tidy .env files.
JWT Token Decoder & Header Inspector
Inspect JSON Web Tokens, parse claims payloads, and verify expiration dates.
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Base64 Encoder & Decoder
Encode plain text to Base64 or decode Base64 strings back to UTF-8 instantly.
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File & Media Base64 Converter
Convert images, PDFs, audio, and documents into Base64 strings, Data URIs, and CSS background snippets.
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Number Base & Binary/Unicode Converter
Real-time conversion across Decimal, Binary, Hexadecimal, Octal, ASCII, and Unicode code points.
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Client-Side AES-256 Text & File Encryptor
Encrypt sensitive messages and confidential files locally with authenticated AES-256-GCM.
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.env Configuration Formatter & Alphabetizer
Clean, alphabetize, and deduplicate environment variable key-value configurations.
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.env Security & Leak Auditor
Scan environment files for exposed secrets, weak passwords, and insecure default keys.
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PII & Sensitive Data Redaction Tool
Automatically mask credit cards, email addresses, phone numbers, and SSNs from logs.
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Data Workshop & SQL Analytics Studio
Query, join, filter, and analyze local CSV, JSON, and Parquet datasets with DuckDB-WASM.
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ZIP Workspace & Archive Manager
Inspect, selectively extract, preview, and create ZIP archives with stream encryption and zip bomb defense.
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Web Assets, SEO Audits, Tokens & AI Architecture
Calculate LLM tokens, audit meta tags, inspect contrast, and optimize front-end code.
HTML & CSS Code Minifier
Compress HTML and CSS code by stripping comments and redundant whitespace for faster load times.
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SVG to PNG High-Resolution Converter
Rasterize vector SVG files into crisp PNG images at custom scale multipliers.
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LLM Token & Cost Estimator (OpenAI, Claude, Gemini & DeepSeek)
Estimate approximate token counts and API inference costs across OpenAI, Claude, Gemini, and DeepSeek models.
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AI Prompt Architect & System Prompt Engineer
Structure high-performance AI prompts with clear persona, context, task, and formatting constraints.
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On-Page SEO Meta & Content Analyzer
Audit title tags, meta descriptions, heading hierarchy, and image alt attributes.
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Interactive Technical SEO Launch Checklist
Track essential pre-launch technical, content, indexing, and mobile SEO requirements.
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Meta Tags & Open Graph Previewer
Preview social share cards for Google, Facebook, Twitter/X, and LinkedIn in real time.
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WCAG Color Contrast Ratio Checker
Evaluate text and background color contrast ratios for WCAG 2.1 AA and AAA compliance.
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ASCII Art & Figlet Banner Generator
Convert plain typography into retro terminal banners and ASCII art text graphics.
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Text to Diagram Editor
Create flowcharts, sequence diagrams, and ER models with Mermaid. Zero server uploads.
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Additional Category Tools
Additional specialized tools and utilities available in this category.
Cryptographic Hash Generator
Compute SHA-1, SHA-256, and SHA-512 cryptographic hashes via native Web Crypto.
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Quick Selection Guide: Which Tool Do You Need?
Format unreadable API response or fix a syntax error in JSON
Token-level parsing preserves BigInt values without rounding; highlights exact error line.
JSON Formatter →Export API JSON data to Excel or Google Sheets for analysis
10-row live preview with delimiter selection (comma/semicolon) and UTF-8 BOM for Excel.
JSON to CSV →Test regular expressions with capture groups and ReDoS timeout safety
Interactive ECMAScript RegExp tester with named groups, match indices, and 2,000 ms Worker guard.
RegEx Tester →Generate cron schedule from plain English description
Transforms "every Monday and Thursday at 9:30 AM" directly into valid 5-part cron syntax.
Natural Language to Cron →Convert raw cURL command into JavaScript fetch, Axios, or Python code
Parses headers, methods, and data payloads into clean executable client code.
cURL Converter →Inspect JWT token headers, payload claims, and expiration date
Decodes Base64Url parts client-side with timestamp translation into readable local dates.
JWT Decoder →Sanitize .env configuration file and verify duplicate keys
Cleans whitespace, deduplicates configuration keys, and structures entries into logical blocks.
.env Formatter →Encode or decode strings and binary data with standard Base64 representation
Fast Unicode-safe UTF-8 Base64 conversion directly in memory.
Base64 Encoder / Decoder →Real Technical Limitations & Browser Constraints
Syntax Validation vs. Business Schema Validation
The JSON Formatter validates syntax according to the official RFC 8259 standard (brackets, quotes, commas, escaped characters). It does not perform automatic repairs (which could silently mutate financial data) nor does it evaluate custom JSON Schema or database business rules.
64-Bit BigInt Token Preservation vs. Downstream Rounding
GoToolstack parses large numbers as string tokens to prevent precision truncation during formatting. However, when consuming formatted JSON in downstream JavaScript runtimes, values exceeding Number.MAX_SAFE_INTEGER (9,007,199,254,740,991) will undergo IEEE 754 float64 rounding unless parsed into BigInt explicitly.
ECMAScript RegExp Engine vs. PCRE Flavors
The RegEx tester uses the native JavaScript (ECMAScript) RegExp engine. While fully supporting lookaheads, lookbehinds, named groups, and unicode property escapes, it does not support PCRE-specific syntax such as recursive patterns (?R) or possessive quantifiers (e.g. *+).
Large Payload DOM Rendering Ceilings
While tokenization and parsing of 50 MB text blocks completes rapidly, rendering hundreds of thousands of syntax-highlighted HTML DOM nodes can cause browser frame drops. Truncate sample batches for optimal interactive browser performance.
Related Practical Guides
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Why CSV Files Break in Excel: Encodings, Delimiters, and Leading Zeros
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Why Your Regex Isn't Matching: Flags, Multiline Anchors, and Escaping
Troubleshoot failed regular expressions. Understand g, i, m, and s flags, multiline ^ and $ anchors, greedy vs. lazy quantifiers, and JavaScript RegExp engine nuances.
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