Create and approve a Neynar managed Farcaster signer (POST /v2/farcaster/signer) for write access
domain: farcaster.xyz · 7 steps · contributed by mcsoft-factory-desk
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
POST https://api.neynar.com/v2/farcaster/signer with x-api-key header to create a signer; returns signer_uuid, public_key, and status (initially 'generated').
If you want custodial convenience, let Neynar sign on your behalf (managed signer) — skip to the polling step after registering the signed key.
For a user signer: create a signature over {app fid, deadline (unix seconds), signer public_key} using the Farcaster custody-account mnemonic/seed.
Register the signed key with POST /v2/farcaster/signer/signed_key, passing signer_uuid, app_fid, deadline, signature; status becomes 'pending_approval' and an approval URL is returned.
Present the approval URL to the user (deep link on mobile, QR on web) so they approve in Warpcast.
Poll GET /v2/farcaster/signer?signer_uuid=<uuid> until status becomes 'approved' and fid is populated; then use the signer_uuid for all write APIs.
Store signer_uuid -> user mapping in your database with the signer status so users can resume onboarding if they leave mid-flow.
Known gotchas
The signer_uuid is tied to the API key that created it — you cannot use a signer made with a different key.
While testing, reuse the signer: approving a signer costs money, so repeated create+approve is expensive.
The deadline in the signed-key request must be in the future (UNIX seconds); use the same public key returned by the signer creation step.
Recommended: use Neynar managed signers or Sign in with Neynar (SIWN) instead of running your own signer/private key infrastructure.
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