Pre-seed · Design partners shipping now

HSM-grade custody,
shipped like an API.

Sigil is a sealed signing appliance with a cloud control plane. Keys stay in hardware. Your app calls one endpoint. Integrators ship in days — not quarters.

Join the waitlist See how it works
// hardware ARM secure core
// api HTTP · gRPC · OpenAPI 3.1
// status End-to-end, running
// what it is

A signing box,
a brain in the cloud,
one clean API.

Today custody is a binary choice: hot wallets are fast and breachable, or cold storage is secure and unscalable. Sigil collapses the tradeoff into a single product with three parts.

01 — the box
A vault the size of a paperback.
Tamper-resistant hardware that holds the keys. Nothing — not us, not the network, not a rogue server — can pull them out.
> keys_in = keys_stay
02 — the brain
A bouncer in the cloud.
Checks who's asking, whether they're allowed, co-signs the request, and routes it to the right box. Every signature gets two names on it.
> validate → approve → route
03 — the plug
One API. Any wallet.
Drop-in SDKs for Ethereum, Solana and MetaMask. If your team can call an HTTP endpoint, you're integrated by Friday.
> POST /sign → done
// use cases

Built for teams who can't choose between secure and shippable.

01 · exchanges
Hot-path withdrawals
Replace a hot wallet without sacrificing throughput. Policy lives in the cloud; keys live in the box. API stays the same.
> drop-in migration
02 · custodians
Programmable cold storage
Ceremony-free workflows for treasuries and qualified custodians. Every signature is dual-signed and auditable.
> sp + octane co-sign
03 · wallet apps
Institutional backend
Wallet-as-a-service providers plug Sigil in behind their existing SDK. MetaMask Snap, Ethereum and Solana out of the box.
> snap · evm · solana
04 · protocols
Validator & operator keys
Run staking, bridge and operator keys inside an appliance instead of a secrets manager. Multi-tenant by design.
> self-hostable
// waitlist

Sign up.
Then sign everything.

We're onboarding our next ten design partners this quarter. Drop your work email — we'll reach out with hardware, docs and a paired onboarding call.

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// for founders
Hardware SDK, cloud credentials and a pre-wired demo appliance.
// for investors
Pre-seed round open. Contact founders@sigilvault.xyz for the deck.
// for engineers
Rust from MCU to cloud. OpenAPI. We're hiring — careers@sigilvault.xyz.

Tweaks