Summary

The SDK wraps all errors in getKeysFromRelayer (network, JSON, deserialization, etc.) as:

"Impossible to fetch public key: wrong relayer url."

This is misleading and hides the true root cause for callers. In real-world usage, the error often has nothing to do with the relayer URL.

Where

src/relayer/network.ts (or equivalent in build output)

Current behavior (simplified):

try {
  // fetch key url, fetch public key, fetch CRS, deserialize
} catch (e) {
  throw new Error('Impossible to fetch public key: wrong relayer url.', { cause: e })
}

Why this is a problem

• Misleads SDK users (sends them debugging the URL when the issue is deserialization, bytes type mismatch, IO errors, etc.)
• Many environments don’t surface cause, so the actual error is lost.

Suggested improvements

• Use a neutral message like:
  • Failed to fetch or deserialize public key
• Or differentiate between error classes:
  • network failure vs JSON parsing vs deserialization vs invalid URL
• Surface original message even when wrapped.

Example change

throw new Error('Failed to fetch or deserialize public key', { cause: e });

Optional: include an error code or custom error type so SDK users can handle it programmatically.

Happy to provide a PR if desired.