The last word stays on your side
The co-signer runs on a machine you control. Chainvara asks it before every signature, and it answers according to your own rules: amounts, destinations, daily budgets, or a person clicking Approve. It also holds your half of split and MPC keys.
t-1041 2,500 USDC → trusted address · auto-approved
t-1042 48,000 USDC → new address · waiting for a person
t-1043 destination differs from approval · refused
t-1044 0.8 BTC → cold storage · approved by Marie
t-1045 daily budget would be exceeded · refused
holding: 4 MPC shares · 2 split-key halves▍
What makes it safe
Your rules, enforced remotely
Approve automatically under a limit, only to known destinations, within a daily budget, or wait for a person.
Holds your key shares
Half of every split key and your FROST share of every MPC wallet stay on your machine, encrypted at rest.
Signed both ways
Every request and answer is authenticated with HMAC and timestamps; replays and tampering are refused.
One file, verifiable
A single Node.js file published with its SHA-256, so you can check exactly what you run.
How it works
- 1
Download and start
Run the co-signer on a server or an always-on PC; it opens a private endpoint.
- 2
Connect it
Paste its URL and shared secret in Developers → API co-signer.
- 3
Set your rules
Limits, allowed destinations, budgets, and which transfers need a person.
Works best with
Ready to see Chainvara in action?
Start free on test networks. Move to production when your controls are in place.