Developer Tools
14 free in-browser developer utilities — convert CSV to JSON, decode JWTs, explain cron expressions, convert Unix timestamps, and more. No server, no account, no rate limits.
CSV to JSON Converter
Paste CSV data and get a clean JSON array. Supports quoted fields, custom delimiters (comma, semicolon, tab), and optional header row mapping.
JSON to CSV Converter
Convert a JSON array of objects to CSV. Auto-detects columns from all records, handles nested values gracefully, and copies output instantly.
Crontab Explainer
Paste a cron expression and get a plain-English explanation of each field. Shows the next 5 scheduled run times with date and time.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and back. Shows UTC, local time, and ISO 8601 formats. Displays the current timestamp live.
JWT Decoder
Decode JWT tokens to inspect the header, payload, and claims as formatted JSON. Shows expiry status and algorithm. No signature verification needed.
YAML ↔ JSON Converter
Convert between YAML and JSON in both directions. JSON to YAML is always complete; YAML to JSON handles standard config-file syntax.
XML Formatter
Paste XML and get it formatted with consistent indentation. Validates syntax and shows clear error messages for malformed markup.
String Escape / Unescape
Escape or unescape strings for JavaScript, JSON, SQL, and regular expressions. Switch between modes instantly.
Number Base Converter
Convert integers between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Live update in all fields.
Hash Generator
Generate SHA-1, SHA-256, and SHA-512 cryptographic hashes from any text input. Runs in-browser using the Web Crypto API — nothing is sent to a server.
URL Parser
Break down any URL into its components: protocol, hostname, port, pathname, query parameters, and fragment. Paste a URL for an instant breakdown.
Color Code Converter
Convert colour codes between HEX, RGB, HSL, and CMYK instantly. Type in any format and all others update live. Includes a colour preview swatch.
HTML Minifier
Minify HTML by removing whitespace, comments, and redundant attributes. Shows original vs compressed size and the percentage reduction achieved.
Markdown to HTML Converter
Convert Markdown to HTML and preview the rendered output side by side. Supports headings, bold, italic, lists, links, images, code blocks, and blockquotes.
About these developer tools
Every tool runs entirely in your browser using JavaScript. None of your data is transmitted to a server — paste a JWT, a CSV file, or a cron expression and the result is computed locally and instantly. This matters especially for JWTs and CSV files that may contain sensitive information.
Is the JWT decoder safe to use with real tokens?
Yes — the decoder runs entirely in your browser and never sends data anywhere. It decodes the header and payload by Base64url-decoding the first two segments. Be cautious pasting production tokens with sensitive claims into any online tool, but this one is fully client-side.
What cron format does the Crontab Explainer support?
It supports standard 5-field Unix cron syntax: minute (0–59), hour (0–23), day of month (1–31), month (1–12), day of week (0–6, Sunday = 0). Each field accepts a number, *, step notation (*/n), ranges (a-b), and comma-separated lists.
How does the CSV to JSON converter handle quoted fields?
It implements the RFC 4180 CSV parsing standard. Fields wrapped in double quotes may contain commas, newlines, and escaped double quotes (""inside a quoted field). It also supports custom delimiters (semicolon, tab) for European-style spreadsheet exports.