Most agents on Solana still run with a base58 secret in an environment variable. The alternatives fall into three shapes: a hosted signer with a policy engine, an on-chain smart wallet with rules in the contract, or a self-hosted signer with an offline root. This is the whole field in one table.
| Who holds the root key | Policy | Cold root | Pricing | |
|---|---|---|---|---|
| a private key in .env | The agent process | None | No | Free |
| Coldstar | You; encrypted on your own drive | Limits, allowlists, daily cap, escalate to human | Yes | Free |
| Turnkey | Turnkey-operated enclaves | Rich Solana instruction rules; no daily caps | No | 25 free signatures/mo, then $0.10 |
| Privy | Privy TEE, Shamir shares | Solana rules; some enforced at API layer | No | Free to 50,000 signatures/mo |
| Crossmint | Owner: you. Agent key: Crossmint TEE | On-chain limits and rolling caps | Owner key could be | Free to 1,000 active wallets |
| Coinbase CDP Wallets | Coinbase Nitro enclaves | Per-transaction Solana rules | No | $0.005 per op; 5,000 free/mo |
| Openfort | Openfort TEE on Google Cloud | Solana rules incl. Anchor IDL checks | No | 2,000 ops free, then $0.01 |
| Para | 2-of-2 MPC: device + Para HSM | Scopes, default deny; API layer | No | Free to 1,200 MAU |
| Dfns | Dfns MPC nodes; threshold undisclosed | Velocity limits, quorum approvals, KYT | No | From $800/year |
| Cubist CubeSigner | Cubist enclave + HSM | Custom Rust/Wasm policies in TEE; MFA quorum | No | Sales |
| Fireblocks | Fireblocks MPC across SGX enclaves | Caps, velocity, designated approvers | No | From $999/month |
| Fordefi | 2-share MPC; you run one share | Allow / Block / Require approval | No | Sales |
| Lit Protocol | Lit TEE network; authority on Base | JavaScript Lit Actions | No | About $0.01 per signature |
| Magic | Magic Nitro enclaves | None documented | No | Free to 1,000 active wallets |
| Web3Auth | Reconstructed on the client at login | None documented | No | Free to 1,000 active wallets |
| Solana Agent Kit | The agent process (KeypairWallet) | None; signer is pluggable | No | Free |
| Alchemy Smart Wallets | BYO or hosted owner; EVM smart account | Session keys, EVM only | No | Compute units |
| Safe + Zodiac Roles | Safe owners, EVM only | On-chain roles, EVM only | Yes, hardware owners | Gas only |
Short cells; the linked pages carry the detail and the sources. Coldstar is beta software with an independent audit planned before its production release, and that is stated on every page.
The one where the agent cannot sign outside a policy and does not hold the root key. Hosted signers with policy engines, on-chain smart wallets with limits, and Coldstar's self-hosted policy signer all satisfy that; a raw key in .env satisfies neither.
Its default KeypairWallet holds a raw keypair in memory. Its BaseWallet interface is pluggable, with examples for Turnkey, Privy, Crossmint, and Para, and Coldstar implements the same interface.
Dfns and Fireblocks (velocity limits), Crossmint (rolling caps on-chain), and Coldstar (daily cap). Turnkey, Privy, Coinbase CDP, and Openfort document per-transaction rules only at review time.
No. Both are EVM-only. On Solana, Squads provides on-chain quorum and spending limits, and Coldstar provides a cold, policy-gated signer.
Open source, MIT. macOS, Linux, Windows — and on the Solana Seeker dApp Store.
pip install coldstar