Developer tools

Convert any API rate limit (per second, minute, hour, day, or month) into daily and monthly quotas instantly. Free, no sign-up. Great for planning API usage.

Format, minify, sort keys, and validate JSON with readable errors. Fully client-side — no account, uploads, or remote storage.

Convert between JSON and YAML with readable formatting and error messages. Fully client-side — no account, uploads, or remote storage.

Turn JSON arrays into CSV or CSV into JSON with header detection. Fully client-side — no account, uploads, or remote storage.

Encode or decode Base64 with UTF-8-safe handling for Unicode, emojis, and binary payloads. Runs locally in your browser.

Percent-encode or decode URLs using encodeURI or encodeURIComponent modes. Fully client-side — no account, uploads, or remote storage.

Parse five-field cron expressions into human-readable schedules and upcoming run times. Fully client-side — no account, uploads, or remote storage.

Compute common digests in hex from any text. Fully client-side — no account, uploads, or remote storage. Runs locally in your browser.

Generate RFC-style UUID v4 and time-ordered v7 identifiers with formatting options. Fully client-side — no account, uploads, or remote storage.

Convert Markdown to clean HTML with a live preview pane. Fully client-side — no account, uploads, or remote storage. Runs locally in your browser.

Free IPv4 subnet calculator: enter an IP and CIDR prefix or subnet mask to get network, broadcast, host range, and wildcard mask instantly. No sign-up.

Convert IPv4 addresses between dotted decimal, binary, hexadecimal, and 32-bit integer formats instantly. Free browser tool — no uploads or sign-up required.

Split a parent CIDR block into equal subnets. Enter 192.168.0.0/16 and target /24 for a full table of network, broadcast, and host ranges.

Expand or compress IPv6 addresses, validate syntax, detect scope (global, link-local, loopback), and view binary hextets. Free browser tool — no sign-up.

Calculate file download or upload time from size and Mbps, or find data volume from speed and duration. Supports metric and binary units. Free, instant.

Look up IANA TCP and UDP port numbers by service name or number. See protocol support, official status, and descriptions for SSH, HTTPS, DNS, and more.

Format MAC addresses to colon, dash, or Cisco dot notation. Validate EUI-48 addresses and look up the OUI vendor prefix. Free browser tool — no sign-up.

Test regular expressions against sample text with highlighted matches and capture groups. Fully client-side — no account, uploads, or remote storage.

Decode JSON Web Tokens to inspect header and payload JSON. Explains signature limits—client-side only; never paste production secrets you cannot rotate.