Open Source (AGPL v3) • Verify the code

The Real-Time
Bitcoin Multisig Coordinator

Stop emailing PSBT files. Coordinate Bitcoin multisig teams instantly. No accounts ~ No database ~ End-to-End Encrypted

Real-time Multisig Signing Demo
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3-of-5 Multisig

Built for Organizational Resilience

Single-signature wallets are a liability for teams.
Multisig ensures no single person—not even the CEO—is a single point of failure.

Flexible "M-of-N" Consensus

Don't be locked into a rigid structure. Whether you need a 2-of-3 for founders or a 3-of-5 for the board, you define the quorum required to authorize funds.

Mitigate "Key Person" Risk

What if the CEO is in an accident or loses access to their keys? In a multisig setup, the remaining board members can still approve payroll, ensuring business continuity.

Security without the friction

Historically, coordinating a board vote on-chain was slow and painful. SigningRoom fixes this. We combine the governance of multisig with the speed of a real-time chat room.

Why change your workflow?

Manual file merging is error-prone and slow. There is a better way.

The Old Way (Email/Slack)

  • Manually merging 5 different email attachments.
  • Files stored permanently on Slack/Google servers.
  • Slow, asynchronous delays between signers.

The SigningRoom Way

  • Real-time merging. Everyone sees the same state.
  • Data lives in RAM, encrypted, and vanishes on expiry.
  • Instant broadcast once signatures are collected.

Orchestrated in Real-Time

The room acts as a blind coordinator, merging signatures as they arrive.

1

Upload PSBT

Export from Sparrow/Electrum. We encrypt it locally.

2

Share Link

Send the secure link. The key is in the URL fragment.

3

Sign & Merge

Signatures are merged automatically. Broadcast once required signatures are collected.

The Blind Relay

We forward your encrypted packets. We never hold the keys.

Client Side
Encrypts with Key
AES-256-GCM
BLIND
The Room (Server)
Stores Encrypted Blob
Sync State
Peer Side
Decrypts via Secret Link

Technical Standards

Built on open Bitcoin protocols and industrial encryption.

BIP-174
PSBT Native
AES-GCM
End-to-End Encrypted
WebSocket
Real-time
Ephemeral
No Logs

Trusted architecture for

Corporate Treasuries
Investment Committees
Remote Teams

Trust through Architecture

We don't ask you to trust us. We built a system where we don't need to be trusted.

Zero Knowledge

Encryption happens in your browser before data leaves. The backend only sees encrypted blobs and cannot read your transaction details.

No Database

Rooms exist only in RAM. There is no persistent database. Once the session expires, the data is gone forever.

Verifiable Code

The client is open source (GPL v3). You can inspect the cryptography code yourself or build the app locally to verify our claims.

Compatible with your Hardware Wallets & Software

SparrowElectrumColdcardTrezorLedgerNunchukBitBox02

Choose your Security Model

From private individuals to corporate treasuries.

Standard Room

Perfect for hobbyists and friends coordinating small multisigs. No account needed.

Free/ forever
  • Up to 3 Signers
  • 20 Minute Ephemeral Window
  • Zero-Knowledge Encryption
Launch Room
Most Popular

One-Off Boardroom

Single-use session for critical transactions requiring audit trails and full board participation.

21ksats / session
  • Cryptographic Audit Log (PDF)
  • Unlimited Signers (M-of-N)
  • 24-Hour Persistence
Start Boardroom
Genesis Keys Remaining
21 / 21

Licensed

For organizations and power users who need on-demand infrastructure.

300ksats / year
or 2.1M sats Lifetime (Genesis)
  • Unlimited Boardrooms
  • Annual Subscription
  • Lifetime Option Available
Get License

Frequently Asked Questions

Where is my private key?

It stays on your hardware wallet or signing device. You only upload a PSBT (Partially Signed Bitcoin Transaction), which contains no private keys, only public data and signatures.

Can you see my transaction details?

No. Your transaction is encrypted in your browser using a key that is contained in the URL link hash (fragment). This key is never sent to our servers, so we literally cannot decrypt your data.

Is it really free?

Yes, for standard use. Basic rooms (max 3 signers, 20 minutes) are free forever.

  • Need more time? Extend any room for 5,000 sats.
  • Need a pro room? Get a 24-hour Boardroom with unlimited signers for 21,000 sats.
  • Team? Grab an annual Corporate License above.

Ready to coordinate?

No accounts required. Just upload a PSBT and share the secure link.

Start New Signing