Free tools
Tools that tell you what is actually happening
Checkers for what your connection exposes, calculators for the network maths, and the everyday developer utilities. No account, no upload where none is needed — every tool says on its own page whether it runs in your browser or asks a server, because that is the part most tool sites leave out.
26 tools shown
- Base64 Encoder & DecoderBoth directions, Unicode-safe, with the URL-safe alphabet when you need it.Runs in your browser
- Browser Fingerprint TestEvery signal your browser hands over automatically, and how much each one narrows you down.Runs in your browser
- DNS Leak TestCheck whether your DNS requests are leaking outside your VPN.Partly server-side
- DNS LookupEvery record a domain publishes, with what they imply about its mail and certificates.Secure lookup
- Full Privacy CheckOne pass over everything you leak: IP, DNS, WebRTC, fingerprint and timezone.Partly server-side
- IP Address LookupLook up the location, ISP and network of any IP address.Secure lookup
- JSON FormatterFormat, validate and inspect JSON — with an error that points at the character.Runs in your browser
- JWT DecoderRead a token’s header and claims, and see what it says about itself. Decoding, not verification.Runs in your browser
- Password GeneratorCryptographically random passwords and passphrases, built on your device.Runs in your browser
- Regex TesterTest a pattern against real text, with matches highlighted and a hard stop on runaway backtracking.Runs in your browser
- Security Headers CheckerWhat each header does, what yours actually says, and the line to add. No letter grade.Secure lookup
- SSL Certificate CheckerRead the certificate a site actually presents — including the broken ones your browser refuses to show you.Secure lookup
- Subnet CalculatorNetwork, broadcast, host range and mask for any IPv4 address and prefix.Runs in your browser
- VPN Protocol RecommenderFive questions, then a straight answer — including “you do not need the stealthy one”.Runs in your browser
- WebRTC Leak TestCheck whether WebRTC is exposing your real IP behind a VPN.Runs in your browser
- What Is My IPSee your public IP, location, ISP and network — instantly.Secure lookup
- ASN LookupWhich network announces an address, and which prefix it sits in.Third-party data
- CIDR CalculatorTurn a CIDR block into its address range — or a range into the smallest blocks that cover it exactly.Runs in your browser
- Cron ParserRead a cron expression in plain English, and see exactly when it will next fire.Runs in your browser
- Internet Speed TestMeasure your real download and upload speed, ping and jitter.Partly server-side
- IPv4 to IPv6 ConverterThe four ways an IPv4 address appears inside IPv6 — and why none of them is “your IPv6 address”.Runs in your browser
- Password Strength CheckerSee what an attacker recognises in your password, and how long it really survives.Runs in your browser
- Subnet Mask ConverterConvert between /24 and 255.255.255.0, in either direction, with the whole table.Runs in your browser
- Unix Timestamp ConverterTimestamps to dates and back, with the unit worked out for you and stated.Runs in your browser
- URL Encoder & DecoderPercent-encoding in all three flavours, side by side, so you can see which one you want.Runs in your browser
- UUID GeneratorGenerate v4 or time-ordered v7 UUIDs, and inspect any UUID you already have.Runs in your browser
Browse by category
Not sure which tool answers your question? Each section explains what the problems in it have in common.
- IP & Network · 12 toolsFind out what your connection looks like from the outside, and do the subnet maths.
- Privacy & Security · 10 toolsTest what your browser and connection give away, and check your defences.
- Encoding & Cryptography · 3 toolsHashes, Base64, JWTs, HMACs and encryption — computed in your browser.
- Domain & Web · 3 toolsInspect DNS records, certificates, redirects, headers and how a page presents itself.
- Developer · 8 toolsFormat, convert, validate and test — without pasting your data into someone else's server.
- Generators · 2 toolsProduce the thing you need: passwords, UUIDs, QR codes, placeholder text, config snippets.
The leak tests are the ones worth running twice.
A single reading tells you very little. Run the IP, DNS and WebRTC checks now, connect, and run them again — the difference between the two is the only thing that proves a VPN is doing what you think it is. JaguarVPN has a free tier, so the comparison costs nothing.