Local-first · No account · Nothing uploaded
Developer tools that run in your browser
135 fast utilities for JSON, text, encoding, crypto, time, networking and more. Local tools never send your data anywhere — and the ones that use the network say so before they run.
Search: try “decode my jwt”…/Popular tools
All 135 tools →JSON & DataRuns locally in your browser.JSON FormatterPretty-print minified or messy JSON with consistent indentation.JSON & DataRuns locally in your browser.JSON to YAMLConvert JSON documents into clean, readable YAML.JSON & DataRuns locally in your browser.CSV to JSONParse CSV or TSV data into a JSON array of objects or rows.EncodingRuns locally in your browser.Base64 EncoderEncode text to Base64, with full UTF-8 support.EncodingRuns locally in your browser.URL EncoderPercent-encode text so it is safe to place in URLs and query strings.EncodingRuns locally in your browser.JWT DecoderDecode a JWT's header and payload and check its expiry — locally.Security & CryptoRuns locally in your browser.SHA-256 GeneratorCompute the SHA-256 hash of any text using Web Crypto.Security & CryptoRuns locally in your browser.UUID GeneratorGenerate cryptographically random UUID v4 identifiers.
Advertisement
Designer Kits
Web & CSSUses the network.Website Style AnalyzerExtract a public page's observed design system — colors, type, spacing, components — with honest confidence.Files & MediaRuns locally in your browser.Image ConverterConvert images between PNG, JPEG, and WebP — without uploading them.Text & RegexRuns locally in your browser.Lorem Ipsum GeneratorGenerate classic lorem ipsum placeholder paragraphs.Web & CSSRuns locally in your browser.CSS FormatterExpand and indent CSS with one declaration per line.
Developer Kits
JSON & DataRuns locally in your browser.JSON FormatterPretty-print minified or messy JSON with consistent indentation.EncodingRuns locally in your browser.Base64 EncoderEncode text to Base64, with full UTF-8 support.EncodingRuns locally in your browser.JWT DecoderDecode a JWT's header and payload and check its expiry — locally.Security & CryptoRuns locally in your browser.UUID GeneratorGenerate cryptographically random UUID v4 identifiers.
Tester Kits
JSON & DataRuns locally in your browser.JSON FormatterPretty-print minified or messy JSON with consistent indentation.EncodingRuns locally in your browser.JWT DecoderDecode a JWT's header and payload and check its expiry — locally.Security & CryptoRuns locally in your browser.UUID GeneratorGenerate cryptographically random UUID v4 identifiers.Text & RegexRuns locally in your browser.Regex TesterTest regular expressions with live match highlighting and group details.
Automation Kits
JSON & DataRuns locally in your browser.JSON to YAMLConvert JSON documents into clean, readable YAML.JSON & DataRuns locally in your browser.CSV to JSONParse CSV or TSV data into a JSON array of objects or rows.Text & RegexRuns locally in your browser.Case ConverterConvert text between camelCase, snake_case, kebab-case, and more.JSON & DataRuns locally in your browser.YAML to JSONConvert YAML documents into formatted JSON.
Web Kits
Web & CSSUses the network.Website Style AnalyzerExtract a public page's observed design system — colors, type, spacing, components — with honest confidence.EncodingRuns locally in your browser.URL EncoderPercent-encode text so it is safe to place in URLs and query strings.NetworkingUses the network.DNS LookupQuery A, AAAA, MX, TXT, CNAME, and NS records for any domain.JSON & DataRuns locally in your browser.JSON MinifierStrip whitespace from JSON to produce the smallest valid payload.
Everyday Kits
Date & TimeRuns locally in your browser.Unix Timestamp ConverterConvert Unix epoch timestamps to human dates and back.Security & CryptoRuns locally in your browser.Password GeneratorGenerate strong random passwords with configurable character sets.Text & RegexRuns locally in your browser.Case ConverterConvert text between camelCase, snake_case, kebab-case, and more.Web & CSSRuns locally in your browser.Markdown PreviewerWrite Markdown and see the rendered result side by side.
Browse by category
API & HTTP
Test requests, parse URLs and headers, and work with the HTTP protocol.
10 Tools
JSON & Data
Format, validate, convert, and inspect JSON, YAML, XML, CSV, and TOML.
20 Tools
Encoding & Decoding
Encode and decode Base64, URLs, HTML entities, hex, Unicode, and JWTs.
16 Tools
Security & Crypto
Hashes, HMACs, checksums, and secure random IDs and passwords.
13 Tools
Regex & Text
Test regular expressions, diff text, and clean up lines and whitespace.
17 Tools
Web Development
Format HTML and CSS, preview Markdown, and convert colors and units.
14 Tools
Date & Time
Convert timestamps, calculate date math, and decode cron schedules.
7 Tools
Networking
Look up DNS records, calculate subnets, and inspect IP addresses.
6 Tools
SQL & Database
Format SQL, generate INSERT statements, and parse connection strings.
5 Tools
Git & Workflow
Generate .gitignore files, commit messages, branch names, and more.
5 Tools
Docker & DevOps
Convert .env files, build docker run commands, and format manifests.
7 Tools
SEO & Meta
Generate meta tags, Open Graph markup, robots.txt, and sitemaps.
5 Tools
File & Media
Convert, resize, and encode images and files — entirely on your device.
6 Tools
Generators
Random numbers, sample JSON, fake data, and mock API responses.
4 Tools
Local by default
Formatting, converting, hashing — it all happens on your device.
Honest about the network
Tools that make requests carry a grey badge naming the destination.
No account, ever
Favourites and recents live in your browser. Nothing to register for.