Free Online Tools
A collection of free network diagnostics and developer tools. Many tools run entirely in your browser for maximum privacy.
Network Tools
Reachability
Check if a website or server is up and responding
Looking Glass
Network diagnostics including ping, traceroute, MTR, and BGP lookups
DNS Propagation Checker
Check DNS record propagation across global DNS servers
Security Scanner
Scan websites for security headers, SSL/TLS configuration, and vulnerabilities
MX Lookup
Look up MX records for a domain to see mail server configuration
WHOIS Lookup
Query WHOIS information for domains and IP addresses
Port Scanner
Scan the top 20 common ports on a target host
DNS Lookup
Query DNS records (A, AAAA, CNAME, TXT, NS, SOA) and perform reverse DNS lookups
What's My IP
Detect your public IP address with geolocation and ISP information
Sysadmin/Operations Tools
Subnet Calculator
Calculate CIDR notation, subnet masks, network ranges, and IP classes
Subnet Splitter & Merger
Split subnets into smaller ranges, merge contiguous blocks, check for CIDR overlaps
Time Tools
Unix timestamp converter, timezone conversion, and ISO 8601 validator
Hash & Encoding
Generate MD5, SHA hashes for text and files, encode/decode Base64, URL, and Hex
JWT Decoder
Decode and inspect JSON Web Tokens, view claims, check expiration status
Email Header Analyzer
Parse email headers, visualize routing hops, verify SPF/DKIM/DMARC
SPF Record Builder
Build SPF records with guided UI, auto-collapse IPs, DNS lookup warnings
Systemd Generator
Generate systemd service unit files with guided UI and templates
Cron Explainer
Parse cron expressions, get human-readable explanations, see next run times
Privacy First
Many of our tools (Subnet Calculator, Subnet Splitter & Merger, Time Tools, Hash & Encoding, JWT Decoder, Email Header Analyzer, SPF Record Builder, Systemd Generator, Cron Explainer) run entirely in your browser. Your data never leaves your device.