Skip to content

tools.gokhangunduz.dev

JSON & data

Format code (Prettier)
Format SQL
JSON ↔ YAML
JSON ↔ CSV
JSON to types
JSON diff
JSON tree viewer

Encode & decode

Base64 encode / decode
URL encode / decode
URL parser
JWT decode / verify

Text

Convert case
Text diff
RegExp tester
Markdown editor

Security & IDs

Hash text
JWT generator
UUID / ULID generator
Password generator

Time

Timestamp converter
Explain a cron expression
Time zone converter

Network

IPv4 CIDR / subnet calculator
DNS lookup
WHOIS / RDAP lookup
IP location and ASN

Images

Convert and resize images
EXIF editor
Image to Base64
QR code generator

Everything runs in your browser; your input never reaches a server.

© 2026 Gökhan Gündüz

IPv4 CIDR / subnet calculator

An IPv4 block's network, broadcast, first and last host and usable host count, /31 and /32 included.

Input