Privy Signer

The Privy signer (github.com/smartcontractkit/crec-sdk/transact/signer/privy) signs CRE Connect operations through Privy's wallet-as-a-service API. It is designed for consumer applications where each end-user has their own embedded wallet.

When to use

Per-user Smart Accounts whose signer is the user's Privy wallet.
Server-side flows that need to act on behalf of a Privy-managed wallet (e.g. policy-gated background jobs).
Existing apps already using Privy for auth and wallet provisioning.

For team-owned signers (production batch jobs, treasury operations) prefer AWS KMS, Vault, or Fireblocks.

Prerequisites

Privy app ID and app secret.
A Privy wallet ID for the user/account this signer drives.
Network egress to https://api.privy.io (or your configured base URL).

Construct the signer

Explicit parameters

import "github.com/smartcontractkit/crec-sdk/transact/signer/privy"

s, err := privy.NewSigner(
    os.Getenv("PRIVY_APP_ID"),
    os.Getenv("PRIVY_APP_SECRET"),
    walletID,
)
if err != nil { return err }

walletID is the user-specific wallet identifier returned by Privy.

From environment

s, err := privy.NewSignerFromEnv()

Reads:

Variable	Required	Notes
`PRIVY_APP_ID`	yes	Your Privy app ID.
`PRIVY_APP_SECRET`	yes	Privy app secret.
`PRIVY_WALLET_ID`	yes	Wallet ID this signer signs for.
`PRIVY_BASE_URL`	no	Defaults to `https://api.privy.io`.

Inject a custom HTTP client (tests)

s, err := privy.NewSigner(appID, appSecret, walletID,
    privy.WithHTTPClient(mockHTTP),
    privy.WithBaseURL("https://api.privy.io"),
)

Read the wallet's address

addr, err := s.GetWalletAddress(ctx)
if err != nil { return err }
fmt.Println("Privy wallet address:", addr)

This is the address you add to AllowedEcdsaSigners when provisioning the corresponding CREC wallet; see Manage Wallet Signers.

Sign an operation

opHash, sig, err := client.Transact.SignOperation(ctx, op, s, chainSelector)

Internally Sign(ctx, hash):

Hex-encodes the digest (0x...).
POSTs /v1/wallets/{walletID}/rpc with method: "secp256k1_sign" and params { "message": "0x...", "encoding": "hex" }.
Authenticates with Basic Auth (appID:appSecret) plus the privy-app-id header.
Returns the raw signature bytes from the response.

The returned signature is suitable for ecrecover with the wallet's address.

Per-request flow

Each Sign call is one HTTP round-trip to Privy. There is no asynchronous approval flow in this signer: Privy handles authentication / authorisation policy internally based on your app config. If you want a confirmation UI, build it client-side before calling the server endpoint that triggers SignOperation.

Using server-side vs. client-side

The Privy signer in the CREC SDK uses the app secret and runs server-side. It is not a browser SDK. The typical architecture is:

The user authenticates with Privy in the browser (Privy frontend SDK).
The user requests an action from your service.
Your service constructs the types.Operation, calls signer.Sign via the Privy server-side signer, submits with Transact.SendSignedOperation.

If you need the user to physically click "Sign" before each operation, surface a confirmation in your UI before the server-side Sign is invoked, and persist the user's intent (signed message, JWT, etc.) so you can prove they consented.

Operational notes

Throughput is bounded by Privy's API quotas; check your plan.
Latency. Each SignOperation makes a single HTTP request to Privy's /v1/wallets/{walletID}/rpc endpoint with method secp256k1_sign. Total latency is set by Privy and the network path between your service and Privy.
Error model. Any non-200 from Privy surfaces as RPC request failed with status <code>: <body>. Inspect the body to distinguish auth failures (401), policy rejections (403), or wallet-not-found (404).

Next steps

Build and Sign Operations: construct the Operation that the Privy signer will sign.
Custom Signer: if Privy's flow doesn't fit, implement your own.

Privy Signer

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