Openfort is the hosted signer whose Solana policy rules look most like Coldstar's: recipient lists, value limits, program IDs, and instruction data validated against an Anchor IDL, checked before a TEE-held key signs. The difference is that the key is in Google Cloud and the check runs in Openfort's backend.
Openfort for app-side wallets under its policy API; Coldstar for the treasury root and the agents that spend from it.
| Coldstar | Openfort | |
|---|---|---|
| Who holds the root key | You. The cold root lives encrypted on your own USB drive. No vendor holds a key, a share, or an account. | Openfort's TEEs for hosted backend wallets, driven by your API key. Key export supported. Self-hosting via OpenSigner (MIT) and Shield (GPL-3.0, Shamir shares) is offered. |
| Where the key lives | On your machine. The air-gapped root signs a bounded policy envelope; a disposable session key signs routine transactions inside it. | Google Cloud TEE hardware, or self-hosted OpenSigner/Shield. |
| Policy engine | Per-transaction limit, daily cap, program allowlist, recipient allowlist and blocklist, escalate-above threshold. Evaluated locally, first match wins, before any signature exists. | Solana rules: recipient address, SPL address, SOL value, SPL value, mint address, program ID, instruction data against an Anchor IDL, network, message regex. Enforced by Openfort's backend on sign, send, sign-message, and sponsor calls. Marketing also lists limits, allowlists, anomaly detection, alerts, and multi-party approvals. |
| Out-of-policy transactions | ESCALATE to a human over air-gapped QR, or REJECT. No signature is produced for a rejected transaction. | Denied. "Human in the loop" and multi-party approvals are claimed on the solutions page; docs detail not confirmed. |
| Cold / offline root | Yes — the root key never touches a networked machine. | No offline root. Self-hostable signer only. |
| Agent integration | Framework-agnostic: the agent proposes an unsigned transaction, the signer decides. CLI signer today; MCP server in progress. | AI-agents solutions page: spend limits, allowlists, secure signing, policy rules in one API. |
| Solana support | Solana mainnet. Core is chain-agnostic; EVM signing exists. | Yes: Solana mainnet-beta and devnet, EOA wallets (smart accounts are EVM-only). |
| Source & self-hosting | Open source (MIT), self-hosted. No API key, no SaaS dependency, nothing to go down. | OpenSigner MIT, Shield GPL-3.0, JS SDK Apache-2.0; the hosted policy engine and TEE service are not open. |
| Pricing | Free software plus a ~$10 drive. | Free for 2,000 operations per month, then $0.01 per operation; Growth $99/month; Pro $249/month; Scale $599/month; Enterprise custom including self-hosted. |
| Maturity | Beta — the signing core and policy engine are in scope for the planned independent audit. | Production; Solana support is recent relative to its EVM history. |
Openfort's Anchor-IDL rule is a good idea and Coldstar's program allowlist is coarser. Where Coldstar pulls ahead is the root: encrypted on your drive, never online, never exportable.
Openfort keeps backend-wallet keys in Google Cloud TEEs and checks its policy rules before signing. The design is sound and the Solana rule set is thorough. You trust Openfort's backend for enforcement, its TEE for the key, and your own API key hygiene; the key can be exported, which is convenient and also a capability an attacker would enjoy.
Coldstar's root cannot be exported because it is never anywhere exportable: an encrypted file on a drive, decrypted into locked RAM offline for microseconds. The agent's session key is disposable, and the policy that bounds it is evaluated on the signing machine.
Openfort is production. Coldstar is beta, pre-audit.
Yes: mainnet-beta and devnet with EOA wallets and a Solana policy rule set. Smart accounts and the 4337 bundler remain EVM-only.
Yes, against an Anchor IDL. Coldstar's policy works at the program and recipient level with amount limits; it does not decode instruction data against an IDL today.
OpenSigner is Openfort's open-source signer for self-hosting one component; the policy engine and TEE service remain Openfort's. Coldstar is self-hosted end to end with the root offline.
Open source, MIT. macOS, Linux, Windows — and on the Solana Seeker dApp Store.
pip install coldstar
Third-party facts were checked against the vendor's own pages on the date above. Pricing and feature sets change; if something here is out of date, tell us and we will fix it.