Data & conversion tools
Move data between JSON, CSV, YAML, XML and back.
100% client-side Free forever No sign-up
Data arrives in whichever format the system that produced it preferred, and it is almost never the format you need next. A colleague sends a spreadsheet export when your importer wants JSON; an API returns nested JSON when you need flat rows for a pivot table; a config comes as YAML when the tool reads TOML. These converters, validators, viewers and diff tools translate between those shapes and tell you clearly when the input is malformed.
Tools in this category
80 Base64 Encode / Decode Convert text to Base64 and back — with proper UTF-8 handling so accents, symbols and emoji survive the round trip. URL Encoder / Decoder Percent-encode text for safe use in URLs, or decode an encoded URL back to readable text. Component and full-URI modes included. Hash Generator (SHA-256, SHA-1, MD5) Compute cryptographic hashes of any text instantly — SHA-256, SHA-1, SHA-384, SHA-512 and MD5, all generated locally on your device. Unix Timestamp Converter Convert epoch seconds or milliseconds to readable dates (local and UTC) and convert any date back to a Unix timestamp — with a live epoch clock. YAML ⇄ JSON Converter Paste YAML to get clean JSON — or JSON to get YAML. Instant validation with precise error messages for malformed input. CSV ⇄ JSON Converter Turn CSV data into a JSON array (header row becomes keys) or flatten JSON back into CSV. Handles commas, semicolons and tabs automatically. YAML Validator Instant YAML syntax check with exact error locations. JSON to TypeScript Interfaces Generate clean TypeScript interfaces from any JSON sample. JSON Path Finder Click any value in your JSON and copy its exact path. MD5 Hash Generator Instant MD5 checksum of any text — private and free. SHA256 Hash Generator Secure SHA-2 hashes computed locally in your browser. File Hash Calculator Verify downloads: checksum any file without uploading it. JSON Diff & Compare Structural JSON comparison — see exactly what changed. Color Format Converter HEX ⇄ RGB ⇄ HSL ⇄ OKLCH with live preview. Image to Base64 Get a copy-paste data URI from any image — fully offline. Number Base Converter Bin ⇄ Oct ⇄ Dec ⇄ Hex — live conversion as you type. Binary ⇄ Text Translator Encode text as binary or decode binary back to text. XML Formatter & Validator Pretty-print and syntax-check XML instantly. JSON to Go Struct Converter Generate Go structs with json tags from any JSON. API Mock Data Generator Realistic fake JSON records for testing APIs. TOML to JSON Converter Parse TOML config and output clean JSON. CSV Editor Online Edit CSV data in a grid and export instantly. Data Size Converter Bytes ⇄ KB ⇄ MB ⇄ GB — decimal and binary units. Roman Numeral Converter Numbers to Roman numerals and back, instantly. JSON to XML Converter Turn any JSON document into indented XML. Unit Converter Online Length, weight, temperature, area, volume, speed. JSON Schema Generator Infer a complete JSON Schema from sample data. Sample Data Generator Fake but realistic rows for testing, JSON or CSV. Visual SQL Query Builder Build SQL queries visually — no typing. SQL to NoSQL Converter Translate SELECT/INSERT/UPDATE/DELETE into MongoDB or DynamoDB syntax GraphQL Playground Format, validate and inspect GraphQL queries without a server Excel Formula Generator Get the right Excel formula for lookups, conditional sums, text and dates — with your own ranges. SQL CREATE TABLE Generator Define columns once, get correct CREATE TABLE DDL for four SQL dialects. SQL INSERT Generator Paste CSV data, get correctly quoted INSERT statements for your SQL dialect. JSON to CSV Converter Turn a JSON array into a clean CSV spreadsheet JSON to SQL Converter Generate INSERT + CREATE TABLE statements from JSON JSON to HTML Table Render a JSON array as clean HTML table markup JSON to Markdown Table Convert a JSON array into a GitHub-ready Markdown table JSON to JavaScript Object Turn JSON into an idiomatic JS object literal JSON to JSONL Converter Convert JSON arrays to newline-delimited JSONL and back JSON to .env Converter Convert JSON config into dotenv variables and back JSON Flattener / Unflattener Flatten nested JSON to dot notation — and reverse it JSON Repair Tool Automatically fix broken or invalid JSON JSON Sort Keys Alphabetize JSON object keys, recursively JSON Stringify / Escape Text Escape text as a JSON string literal — and back CSV to SQL Converter Generate INSERT statements from CSV data CSV to XML Converter Turn CSV rows into well-formed XML CSV to YAML Converter Convert CSV rows into a YAML record list CSV to TSV Converter Switch between comma- and tab-separated data CSV to HTML Table Render CSV data as clean HTML table markup CSV to Markdown Table Turn CSV data into a GitHub-ready Markdown table CSV Column Extractor Keep, reorder or drop CSV columns in seconds CSV Diff Spot added, removed and changed rows between two CSVs XPath Tester Run XPath queries against XML instantly INI to JSON Converter Convert INI config files to JSON and back .env Diff Compare two dotenv files variable by variable JSON to C# Converter Turn JSON into ready-to-paste C# classes JSON to Java Converter Turn JSON into ready-to-paste Java classes JSON to Kotlin Converter Turn JSON into ready-to-paste Kotlin data classes JSON to Swift Converter Turn JSON into ready-to-paste Swift structs JSON to Rust Converter Turn JSON into ready-to-paste Rust structs JSON to Dart Converter Turn JSON into ready-to-paste Dart classes JSON to Python Converter Turn JSON into ready-to-paste Python data classes JSON to Pydantic Converter Turn JSON into ready-to-paste Pydantic models JSON to PHP Converter Turn JSON into ready-to-paste PHP classes JSON to Zod Converter Turn JSON into ready-to-paste Zod schema JSON to GraphQL Converter Turn JSON into ready-to-paste GraphQL schema JSON to Protobuf Converter Turn JSON into ready-to-paste Protobuf schema JSON to Excel Converter Turn a JSON array into a downloadable .xlsx spreadsheet JSON to Mongoose Schema Generator Infer a ready-to-use Mongoose schema from sample JSON JSON to Prisma Schema Generator Turn sample JSON into a Prisma model in one click JSON Viewer Explore any JSON payload as a readable tree JSON Schema Validator Check any JSON document against its schema with Ajv XML to JSON Converter Turn any XML document into clean JSON XML to CSV Converter Extract repeating XML records into a CSV table YAML Diff Tool Compare two YAML documents key by key TOML Formatter & Validator Validate, format and convert TOML in one place Merge CSV Files Combine multiple CSV files into a single table Split CSV File Break a large CSV into equal chunks with headers NDJSON to JSON Converter Convert JSON Lines to a JSON array — and back
About these tools
Flat and nested do not map cleanly
CSV is a rectangle: rows and columns, one value per cell. JSON is a tree, with objects inside arrays inside objects. Converting a tree to a rectangle always requires a decision about what to do with the nesting — flatten it into dotted column names, or serialise the branch into a single cell. Being aware that the choice exists is what stops a conversion from quietly losing half your data.
Validate before you blame the parser
Most "the import is broken" reports are malformed input: a trailing comma, an unquoted field containing a delimiter, a tab where a space belonged, or a byte-order mark at the start of the file that makes the first column name look wrong. A validator points at the offending line and column, which turns half an hour of squinting into a five-second fix.
Big files, one browser tab
Everything here runs client-side, so the practical limit is your own memory rather than an upload cap or a paid tier. A multi-megabyte export processes locally in seconds and never leaves the machine — which also means you can run a real customer export through a converter without it becoming a data-transfer question for someone else to answer.