Free Online Tools
A collection of free network diagnostics and developer tools. Many tools run entirely in your browser for maximum privacy.
Network Tools
Is It Down?
Check if a website is down for everyone or just you, with site preview and response details
Reachability
Check if a website or server is up and responding
Looking Glass
Network diagnostics including ping, traceroute, MTR, and BGP lookups
Routing Loop Detector
Detect routing loops in network paths by analyzing traceroute patterns
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
Mail Blacklist Checker
Check if an IP address or domain is listed on major email blocklists (Spamhaus, SpamCop, Barracuda, etc.)
AS-SET Validator
Expand AS-SET objects from IRR databases, view member ASNs and generate IPv4/IPv6 prefix lists
RPKI Validator
Validate BGP route origin authorisation, check ROA coverage for any IP prefix and AS number
DNSSEC Validator
Validate DNSSEC configuration, check DNSKEY, DS, and RRSIG records for any domain
Mail SSL Checker
Check SSL/TLS on IMAP, POP3, and SMTP ports. Test STARTTLS, view certificates and cipher suites
SSL Expiry Monitor
Check SSL certificate expiry dates and subscribe for daily email alerts
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
SPF Record Validator
Validate SPF records against RFC 7208, check DNS lookup limits, policy strength, and misconfigurations
ZFS RAID Calculator
Calculate usable storage, parity overhead, and fault tolerance for ZFS pools
Chmod Calculator
Convert between octal (755), symbolic (rwxr-xr-x), and checkbox Unix file permissions
Password Generator
Generate cryptographically secure passwords, passphrases, and API keys
htpasswd Generator
Generate Apache and Nginx basic authentication password entries
Firewall Rule Generator
Build UFW, iptables, and nftables firewall rules with a guided interface
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
JSON / YAML Formatter
Format, validate, and convert between JSON and YAML with auto-detection
Web Server Config Generator
Generate configuration files for Caddy, Nginx, Apache, and HAProxy with templates
QR Code Generator
Generate QR codes for URLs, text, WiFi, email, and phone numbers
Privacy First
Many of our tools (Subnet Calculator, Subnet Splitter & Merger, Time Tools, Hash & Encoding, JWT Decoder, Email Header Analyzer, SPF Record Builder, SPF Record Validator, ZFS RAID Calculator, Chmod Calculator, Password Generator, htpasswd Generator, Firewall Rule Generator, QR Code Generator, Systemd Generator, Cron Explainer, JSON / YAML Formatter, Web Server Config Generator) run entirely in your browser. Your data never leaves your device.