Free OnlineDeveloper Tools

Format JSON, encode Base64, decode JWT, convert YAML, and more — right in your browser.

56 tools · no signup · your data stays on your device

JSON

13

JSON Formatter & BeautifierFormat and beautify JSON with syntax highlighting JSON ValidatorValidate JSON syntax and structure JSON DiffCompare two JSON objects and highlight differences JSON Pretty PrintPretty print JSON with customizable indentation for readability JSON MinifierMinify and compact JSON by removing whitespace JSON to YAMLConvert JSON to YAML format JSON to CSVConvert JSON array to CSV format JSON to TypeScriptGenerate TypeScript interfaces from JSON JSON to C# ClassGenerate C# classes from JSON JSON to Go StructGenerate Go structs from JSON JSON to PythonGenerate Python dataclasses from JSON JSON to JavaGenerate Java POJO classes from JSON JSON to DartGenerate Dart classes from JSON with fromJson and toJson

YAML

1

YAML to JSONConvert YAML to JSON format

Base64

7

Base64 Encode OnlineEncode text or binary data to Base64 Base64 Decode OnlineDecode Base64 encoded text Base64 Image DecoderDecode Base64 data URIs back to viewable images Base64 Image EncoderEncode images to Base64 data URIs for HTML and CSS Base64 URL-safeEncode and decode URL-safe Base64 (Base64url)Base64 to HexConvert between Base64 and hexadecimal Base64 File EncoderEncode any file to Base64 — PDF, ZIP, images, and more

URL

2

URL Encode OnlineEncode special characters in URLs URL Decode OnlineDecode percent-encoded URLs

JWT

2

JWT EncoderCreate and sign JSON Web Tokens with HS256, HS384, HS512 JWT DecoderDecode and inspect JSON Web Tokens

Time

4

Timestamp ConverterConvert Unix timestamps to human-readable dates and back Cron Expression ParserParse cron expressions into human-readable descriptions and preview next run times Cron Expression GeneratorGenerate cron expressions visually with a step-by-step builder Cron Expression ValidatorValidate cron expressions and see a detailed field-by-field breakdown

UUID

10

UUID v4 GeneratorGenerate cryptographically random UUID v4 UUID v1 GeneratorGenerate time-based UUID v1 with embedded timestamp UUID v7 GeneratorGenerate time-ordered UUID v7 for database primary keys UUID v3 GeneratorGenerate deterministic name-based UUID v3 using MD5 UUID v2 GeneratorGenerate DCE Security UUID v2 with local domain and ID ULID GeneratorGenerate lexicographically sortable unique IDs NanoID GeneratorGenerate tiny URL-safe unique IDs with customizable alphabet CUID GeneratorGenerate collision-resistant unique IDs (CUID v1)CUID2 GeneratorGenerate secure next-generation CUID2 identifiers UUID DecoderDecode and inspect UUID structure, version, and embedded data

Hash

7

MD5 Hash GeneratorGenerate MD5 hash from any text SHA-1 Hash GeneratorGenerate SHA-1 hash from any text SHA-256 Hash GeneratorGenerate SHA-256 hash from any text SHA-384 Hash GeneratorGenerate SHA-384 hash from any text SHA-512 Hash GeneratorGenerate SHA-512 hash from any text HMAC GeneratorGenerate HMAC signatures with SHA-256, SHA-384, or SHA-512 Hash IdentifierIdentify hash type by length and format — MD5, SHA-1, SHA-256, and more

CSV

5

CSV to JSONConvert CSV data to JSON array or object format CSV to MarkdownConvert CSV to a Markdown table CSV to HTML TableConvert CSV to an HTML table CSV FormatterFormat and normalize CSV data with custom delimiter options CSV to SQLGenerate SQL INSERT statements from CSV data

Text

5

Word CounterCount words, characters, sentences, paragraphs and estimate reading time Case ConverterConvert text between uppercase, lowercase, title case, camelCase, snake_case and more Lorem Ipsum GeneratorGenerate lorem ipsum placeholder text with configurable paragraphs and words Line SorterSort lines alphabetically, by length, reverse or randomize line order Duplicate Line RemoverRemove duplicate lines from text, keeping only unique lines

Developer tools that just work

ToolDeck is a free collection of online utilities built for developers who need fast, reliable tools without friction. Format and validate JSON, encode or decode Base64, inspect JWT tokens, convert between JSON and YAML, encode URLs, and convert Unix timestamps — all without signing up, installing anything, or leaving your browser. Every tool runs entirely client-side, so your data stays on your device.