Developer Tools
Developer tools that stay on your device.
Decode tokens, format JSON, and inspect encodings without sending anything to a server. No signup, no upload, no telemetry on the data you paste.
JWT Decoder
Decode JSON Web Tokens, inspect claims, and check expiry without uploading the token.
JWT Encoder
Sign JSON Web Tokens locally with HS, RS, PS, or ES algorithms. Header, payload, and signing key never leave your browser.
JSON Formatter
Format, minify, validate, repair, and sort JSON. JSONPath queries, inline tree editing, CSV export, and shareable permalinks — all in the browser.
Base64
Encode and decode standard and URL-safe Base64 with full UTF-8 awareness.
URL Encoder
Percent-encode and decode URLs. Component, full-URI, and form-urlencoded modes.
Hash Generator
Compute MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes side by side.
UUID Generator
Generate v4, v7, NIL, and MAX UUIDs with hyphen, case, and brace formatting.
Timestamp Converter
Convert between Unix seconds, milliseconds, and ISO 8601. Pick a timezone, see derived day-of-year and ISO week.
Regex Tester
Test JavaScript regular expressions with match highlighting, capture groups, and a Web Worker timeout against catastrophic backtracking.
Diff Checker
Compare two texts side-by-side or in unified view. Optional ignore-whitespace and ignore-case modes.
JSON ↔ YAML
Convert between JSON and YAML, both directions, with multi-document support and exact line-and-column error reporting.
CIDR Calculator
Compute IPv4 and IPv6 subnet info from CIDR notation: network, host range, total addresses, masks, scope, classful info.
Cron Parser
Decode cron expressions to a human description, the next 5 runs, and a per-field breakdown.
JSON Schema Validator
Validate JSON against a schema with full error paths. Draft-07 and 2020-12, format checks, all-errors mode.
HTTP Status Codes
Searchable reference for HTTP status codes with descriptions and RFC references.
cURL ↔ fetch
Convert cURL commands to JavaScript fetch() calls and back, in your browser.
Markdown Preview
Type Markdown, see HTML. CommonMark plus tables and strikethrough, with raw HTML escaped and links sanitized.