About

techutils.net is a set of small, focused tools for technical work. Each tool does one job. 22 of the 25 run entirely in your browser and don't send what you type to our servers; What's my IP, DNS lookup and MAC address lookup send only what they need to work. Each tool's page says how it handles your input, and the privacy policy lists every tool.

The tools

• JSON formatter: Format, validate, minify and explore JSON. Query it, repair it, or check it against a JSON Schema.
• Regex tester: Test a JavaScript regular expression against sample text: see every match and capture group, try flags, and preview a replacement.
• Text diff: Compare two texts and see the lines, words or characters that changed, side by side or inline, with a unified patch to copy.
• Case converter: Convert text to camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, dot.case, Title, Sentence, lower or UPPER case.
• YAML to JSON: Convert YAML to JSON and back: several documents, anchors and aliases, YAML 1.2 or 1.1 booleans, exact big integers, and errors with their line and column.
• CSV to JSON: Convert CSV to JSON and back: separator detection, header rows, numbers kept exact (zip codes and IDs stay text), nested objects flattened, large files.
• SQL formatter: Format and indent SQL for PostgreSQL, MySQL, SQL Server, Oracle, SQLite, BigQuery and other dialects, with keyword case and indent options.
• Subnet calculator: Network, broadcast, host range and mask for any IPv4 or IPv6 block, and equal splits.
• VLSM calculator: Subnets sized from host counts, packed without overlaps, with CSV and Terraform export.
• What's my IP: Your public IP address (IPv4 or IPv6) with its approximate location, network and connection details, read by our server from the request and not logged by us.
• DNS lookup: Look up a domain's A, AAAA, CNAME, MX, TXT, NS, SOA and CAA records, or the name behind an IP address, from a public DNS resolver of your choice.
• IP range to CIDR: Convert IPv4 and IPv6 address ranges to the fewest CIDR blocks that cover them exactly, merge lists of ranges, or turn CIDR blocks back into ranges.
• MAC address lookup: Find the manufacturer of a network device from its MAC address in the IEEE registry, and see whether the address is random, multicast or broadcast.
• Base64 encoder: Encode text or a file to Base64 or Base64url, or decode Base64 back to text, an image or a file, with line wrapping and data URLs.
• URL encoder: Percent-encode or decode text, query values and whole URLs, and see a URL's parts and query parameters decoded.
• HTML entity encoder: Encode text as HTML entities (&, <, ", numeric references) or decode every named and numeric entity back to text.
• QR code generator: Make a QR code for a link, text, Wi-Fi network, email, phone, SMS or contact card, in your colours, and download it as SVG or PNG.
• JWT decoder: Decode a JSON Web Token's header and payload, see its claims and times in your time zone, and verify its signature with a secret or public key.
• Hash generator: Get the SHA-256, SHA-384, SHA-512, SHA-1 and MD5 hashes or HMACs of text or a file, and check a file against a published checksum.
• UUID generator: Generate version 4 (random) and version 7 (time-ordered) UUIDs, one or in bulk, and inspect any UUID's version, variant and time.
• Password generator: Generate strong random passwords or passphrases: length, character sets, look-alike characters left out, strength in bits.
• Timestamp converter: Convert Unix timestamps in seconds, milliseconds, microseconds or nanoseconds to dates in UTC and any time zone, and dates back to timestamps.
• Time zone converter: Convert a date and time between time zones: local time, date, UTC offset and daylight saving for each zone, with the day it falls on.
• Cron parser: Read a cron expression in plain English, see what each field means and list its next runs in any time zone. Unix cron and Quartz.
• chmod calculator: Convert Unix file permissions between octal (755), symbolic (rwxr-xr-x) and checkboxes, with setuid, setgid and sticky bits, and copy the chmod command.

How the tools are checked

• The subnet calculator's results are tested against Python's ipaddress module on 1,011 generated cases, and property tests check that every split fills its block exactly and every VLSM plan stays inside its block without overlaps.
• The JSON formatter is built on vanilla-jsoneditor; our end-to-end checks cover formatting and views.

If you find a wrong result, please tell us.

Accessibility

If something doesn't work with your keyboard, screen reader or other assistive technology, email hello@techutils.net and tell us what you were trying to do.

Contact

hello@techutils.net. To report a security problem, see security.txt.