ButterShare - Send large files free with no size limits, zero cloud storage, and no signup. Fast, encrypted peer-to-peer file transfer for any modern browser.

ButterShare

Send large files free with no size limits, zero cloud storage, and no signup. Fast, encrypted peer-to-peer file transfer for any modern browser.

Core Capabilities

ButterShare is a browser-based peer-to-peer file transfer tool built to stream files directly between devices without relying on intermediate cloud storage. It establishes encrypted WebRTC connections between senders and receivers, with no application-level file size caps. The practical maximum transfer size is determined only by the sending and receiving device’s available disk space, browser capabilities, and network conditions.

The tool supports up to 10,000 files per single transfer session, and preserves full nested folder directory structures so files arrive organized exactly as they were selected, with no required manual zipping step before sharing. When a direct peer-to-peer connection cannot be established due to firewall or network restrictions, ButterShare automatically falls back to an encrypted TURN relay that forwards DTLS-encrypted traffic between devices without storing any file data.

ButterShare uses the browser’s Origin Private File System (OPFS) to stream file chunks directly to local disk, enabling transfers of files larger than the host device’s RAM without performance issues. If a connection drops mid-transfer, the session can be resumed using local browser checkpoint data stored on both the sender and receiver’s devices.

To initiate a transfer, users select files or folders, and ButterShare instantly generates three sharing options: a standard web link, a scannable QR code, or an 8-character ephemeral room code. All transferred file chunks are protected with end-to-end encryption, with cryptographic keys held exclusively by the two connected devices, so no third party including ButterShare can access unencrypted file content. No file data is ever persisted to cloud storage during any stage of a transfer.

Supported Workflows

ButterShare’s 3-step transfer flow requires no pre-configuration or account creation:

1. Choose Files: Select individual files or entire folders directly from your device, with no upload queues or pre-processing required.

2. Share Access: Distribute the generated link, QR code, or 8-character room code to the recipient via any messaging, email, or collaboration platform.

3. Stream Directly: Once the recipient opens the share link in their modern browser, the two devices establish a direct encrypted connection and begin streaming file chunks in real time, written directly to the recipient’s local disk.

Transfers work seamlessly over local Wi-Fi networks to leverage gigabit local speeds, or over wide area networks for remote collaborators. No companion apps, cables, or platform-specific setup is required for either party.

Target Audiences

ButterShare is engineered for users who regularly work with large payloads that hit limits on traditional cloud file sharing services:

• Video editors and filmmakers sending batches of raw 8K B-roll, ProRes 4444 footage, and DaVinci Resolve project files to colorists, directors, and post-production teams

• Game developers and 3D artists sharing Unreal Engine 5 builds, textured Blender assets, Unity project files, and animation rigs without cloud upload delays

• Developers and DevOps teams transferring PostgreSQL database snapshots, Docker container images, and Linux ISO files with full bit-level integrity and no intermediate cloud footprint

• Music producers collaborating on lossless 24-bit 96kHz WAV stems, Ableton sessions, and Logic project files with no quality degradation

• Legal and enterprise teams transferring confidential NDA documents, financial audit records, and sensitive M&A materials that require strict zero-knowledge privacy

• General users needing to send large files or folders without hitting arbitrary size caps, creating accounts, or waiting for multi-hour cloud uploads.

Platform Support

ButterShare runs on any device with a modern browser, including Windows, macOS, Linux, iOS, Android, and ChromeOS. Chromium-based browsers (Chrome, Edge, Brave, Opera) and Firefox support full OPFS disk streaming for very large transfers. Safari supports all transfer functionality, with practical constraints tied to available browser memory on the host device.

Pricing

All core ButterShare features are 100% free forever, with no hidden upsells, subscription tiers, or paywalls for large transfers.

Known Limitations

• Transfer speed may be limited by the sender or receiver’s available network bandwidth, or local network hardware constraints

• Safari browser transfers are subject to built-in browser memory limits that may restrict maximum payload size for very large single-file transfers.