invalid signature length

viem (TypeScript) — recoverMessageAddress / recoverAddress / recoverTypedDataAddress / recoverPublicKey

What it means

viem's recovery functions accept a hex or byte signature of exactly 65 bytes (r‖s‖v) and stop with this plain `Error` for any other length — including the 64-byte EIP-2098 compact form, which viem supports only through explicit conversion helpers. Nothing was recovered; the signature is in a different format, or it is not an EOA signature at all.

Why it happens

• A 64-byte compact (EIP-2098) signature

  common

  Some wallets, relayers and contracts store signatures in the compact form (yParity folded into s). ethers accepts it directly; viem's `recover*` functions do not.

• A smart-account signature

  common

  ERC-1271 and ERC-6492 signatures from Safe, Coinbase Smart Wallet or other smart accounts are longer than 65 bytes and cannot be recovered to an address; they must be checked against the account contract.

• Base64 or double-hex encoding

  occasional

  A signature transported as base64, or a hex string encoded again as hex, has the wrong length once viem reads it.

How to fix it

1. 1.

   Convert compact signatures before recovering

   `parseCompactSignature` plus `compactSignatureToSignature` turns the 64-byte form into the 65-byte one.

   import { compactSignatureToSignature, parseCompactSignature, recoverMessageAddress, serializeSignature, size } from "viem";
   
   const sig = size(signature) === 64
     ? serializeSignature(compactSignatureToSignature(parseCompactSignature(signature)))
     : signature;
   const signer = await recoverMessageAddress({ message, signature: sig });

2. 2.

   Use publicClient.verifyMessage for wallets in general

   A public client verifies EOA signatures locally and smart-account signatures through ERC-1271/ERC-6492, so the same code works for every wallet type.

   import { createPublicClient, http } from "viem";
   import { mainnet } from "viem/chains";
   
   // Handles EOAs, ERC-1271 smart accounts and ERC-6492 (undeployed) accounts.
   const client = createPublicClient({ chain: mainnet, transport: http(process.env.RPC_URL) });
   const valid = await client.verifyMessage({ address, message, signature });

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