Guides
Everything here is written and verified by the people who build ShareDrop.org. Each article states when it was last checked and what it was tested against.
Concepts
How Browser-to-Browser File Transfer Actually Works
A plain-language walkthrough of WebRTC data channels: how two browsers find each other, negotiate an encrypted link, and move file bytes without a server in the middle.
STUN, TURN and ICE, Explained Without Jargon
What actually happens when a WebRTC connection is being set up: the roles of STUN, TURN and ICE, and why a relay is sometimes unavoidable.
Direct P2P vs Encrypted Relay: What Is the Real Difference?
Speed, privacy and reliability trade-offs between a direct WebRTC connection and a TURN relay — and what the relay can and cannot see.
Why Some Networks Refuse Direct WebRTC Connections
NAT types, CGNAT, UDP-blocking firewalls and enterprise proxies: the network conditions that force WebRTC traffic through a relay.
Is a WebRTC Data Channel Encrypted? Yes — Here Is How
DTLS, SCTP and certificate fingerprints: the encryption WebRTC mandates, what it protects against, and the one attack it cannot stop on its own.
How a Safety Code Proves You Are Connected to the Right Device
Why encrypted is not the same as authenticated, and how comparing a short code derived from DTLS fingerprints detects a man-in-the-middle.
Why Large Files Crash Browser Tabs (and How Streaming Fixes It)
Memory limits, Blob buffering, the File System Access API and backpressure: what it takes to move a file bigger than your RAM through a browser.
Step-by-step guides
How to Know a Received File Is Complete and Uncorrupted
Transfer finished does not mean file intact. How end-to-end SHA-256 verification works and why ShareDrop.org refuses to mark a file done without it.
Send Files From an iPhone to a Windows PC (No App, No Cable)
A step-by-step guide to moving photos, videos and documents from iOS Safari to a Windows browser with an end-to-end encrypted link.
Troubleshooting
How a VPN Changes (or Breaks) WebRTC File Transfers
What VPNs do to ICE candidates, why some corporate VPNs force every byte through a relay, and how to diagnose it.