DNS Lookup
Featured
Look up DNS records for a domain.
- Online lookup
- No signup
Developer topic guide
Network tools
DNS, WHOIS, SSL, HTTP headers, and cURL helpers for quick network debugging on your device.
6 free tools in this guide — pick one below to get started.
Tools in this guide(6)
Open a tool to calculate, convert, or edit — no signup required.
WHOIS Lookup
Featured
Look up domain registration details via RDAP.
- Online lookup
- No signup
SSL Checker
Featured
Check certificate transparency records for a domain.
- Online lookup
- No signup
cURL Builder
Featured
Build curl commands from method, URL, headers, and body.
- On your device
- No signup
cURL Formatter
Featured
Parse and format curl commands for readability.
- On your device
- No signup
Short Link Generator
Featured
Create compact short links for long URLs.
- On your device
- Secure processing
- No signup
Overview
Network tools query public infrastructure data: DNS records, domain registration summaries, certificate expiry, and response headers. They complement browser DevTools when you need an external vantage point.
Lookups use online directories and may be slow during busy times. Results can be cached or incomplete for private hosts. Short Link Generator creates redirect URLs when testing campaigns.
Do not use WHOIS or DNS output as sole security proof — combine with SSL Checker and your own monitoring.
How to choose
- Record lookup → DNS Lookup.
- Domain registration → WHOIS Lookup.
- HTTPS cert expiry → SSL Checker.
- Response inspection → HTTP Header Checker (SEO & Webmaster category).
- Request builder → cURL Builder.
Frequently asked questions
Do lookups run on my device only?
Network tools query external services. Your query leaves the browser to reach DNS/WHOIS providers.
Why is WHOIS redacted?
Many registrars hide personal data under privacy services.
Can I test internal hostnames?
Public lookup tools cannot resolve private intranet names.
Step-by-step workflows (10)
Multi-step guides that chain tools from this topic—follow numbered steps instead of guessing tool order.
- Debug a JWT or API tokenDecode a bearer token, pretty-print JSON claims, and inspect Base64 segments.3 steps
- Provision staging credentialsGenerate passwords, UUIDs, and hashes for dev, QA, and fixture data.3 steps
- Debug a failing APIReproduce the request, format the JSON response, inspect JWTs, and compare payloads.5 steps
- Validate JSON before deployValidate syntax, pretty-print, generate a schema draft, and diff against the previous payload.4 steps
- Ship a CSS UI tweakPrototype in the playground, generate layout and effect CSS, then check contrast.6 steps
- Turn a spreadsheet into an API payloadPreview CSV, convert to JSON, format, and validate before posting to an API.4 steps
- Verify a download with checksumsHash the file you downloaded, compare digests, and encode strings when docs ship Base64.3 steps
- Pre-launch domain and TLS checkConfirm DNS, WHOIS, SSL certificates, and security headers before go-live.4 steps
- Write and test a regexTest patterns live, consult cheat-sheet examples, and diff sample outputs.3 steps
- Backend ops cheat sheetBuild cron schedules, explain expressions, convert timestamps, and tidy env files.4 steps