23 free tools, with more on the way
Free online tools
that just work.
Security checks, network tests, generators and calculators for IT pros, businesses and anyone else who needs a job done. No sign-up, no paywall.
- Tools
- 23+
- Cost
- £0
- Sign-ups
- None
- Categories
- 5
Spotlight
Flagship tools
The tools we're building first, all designed for speed and privacy.
Secure Shared Clipboard Transfer
Share text, passwords, screenshots and files between two computers with a private link. Encrypted, and wiped after 48 hours.
Smart QR Code Generator
QR codes for links, Wi-Fi, contacts and more, in your own colours, as PNG or SVG.
Cyber Essentials Checker
Answer guided questions to see how ready your organisation is for UK Cyber Essentials certification.
Internet True Line Capacity Speed Test
Measure real download, upload, latency and jitter to see what your line can actually deliver.
The toolbox
All tools
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1 of 23 tools
Secure Shared Clipboard Transfer
Share text, passwords, screenshots and files between two computers with a private link. Encrypted, and wiped after 48 hours.
Cyber Essentials Checker
Answer guided questions to see how ready your organisation is for UK Cyber Essentials certification.
Password Generator
Strong random passwords and memorable passphrases, generated in your browser.
Password Strength Tester
See how long a password would take to crack. It never leaves your device.
Email Security Checker
Check a domain's SPF, DKIM and DMARC records and spot spoofing risks.
SSL Certificate Checker
Inspect a site's certificate, its expiry date, the full chain and the TLS versions it supports.
Hash Generator
Create SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or files.
Internet True Line Capacity Speed Test
Measure real download, upload, latency and jitter to see what your line can actually deliver.
What's My IP
Your public IP address, who your internet provider is, your reverse DNS and what your browser reveals about you.
ISP Leak & Blocking Detector
Check whether your internet provider or VPN is leaking your real IP through WebRTC, or blocking websites on your connection.
DNS Leak Checker
See which DNS servers really answer your lookups, so you can tell if your VPN or private DNS is leaking.
DNS Checker & Propagation
Look up any DNS record, compare answers across six public resolvers and the authoritative servers, trace a lookup from the root and check DNSSEC.
Subnet Calculator
Work out network ranges, masks, broadcast addresses and usable hosts.
HTTP Header Checker
See the response headers, redirect chain and security headers for any URL.
Smart QR Code Generator
QR codes for links, Wi-Fi, contacts and more, in your own colours, as PNG or SVG.
UUID Generator
Generate v4 and v7 UUIDs one at a time or in bulk.
JSON Formatter & Validator
Pretty-print, minify and validate JSON with clear error messages.
Base64 Encoder / Decoder
Encode text and files to Base64, or decode them back.
Unix Timestamp Converter
Convert between Unix time and readable dates in any time zone.
Colour Converter & Contrast
Convert between HEX, RGB and HSL, and check WCAG contrast between two colours.
UK VAT Calculator
Add or remove VAT at 20%, 5% or a custom rate.
Download Time Calculator
Find out how long a file will take to transfer at a given line speed.
Percentage Calculator
Percentages of numbers, percentage change, increases and decreases.
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Show all toolsWhy osir
Built by IT pros, free for everyone
Free, for good
Every tool is free to use. There are no trials, credits or premium tiers.
No sign-up
Open a tool and use it. No accounts, emails or passwords.
Private by design
Where possible, tools run in your browser, so your data never leaves your device.
Fast and lightweight
Hand-written code with no frameworks, ads or third-party trackers. It works on any device.
Brought to you by
Made possible by our partners
osir's free tools are built and supported by three technology companies.