Neynar

Neynar is the leading developer platform for Farcaster — a decentralized social protocol. It exposes the Farcaster social graph (users, casts, channels, follows, reactions) through a clean REST API.

In Agent Forge, the Neynar integration lets workflows query the Farcaster network — look up users by FID, username, or verified Ethereum address; fetch casts and their reply threads; search posts; list channel members; retrieve trending feeds; track reactions and notifications. Use it to power Farcaster-native agents, content monitoring, sentiment analysis, audience research, crypto-twitter-style automation, and any workflow that needs first-class social-graph data.

This is a bring-your-own-key (BYOK) integration. Each user supplies their own Neynar API key.

Usage Instructions

Pick an operation, paste your Neynar API key, and fill in the required identifier (FID, username, address, cast hash, channel ID, or search query). All paginated operations support limit and cursor in advanced settings. Many operations accept a viewer_fid so responses include "did the viewer like/follow/recast this" context.

Tools

Users

• neynar_user_by_fid - Look up one or many users by FID (bulk endpoint)
• neynar_user_by_username - Look up a user by @username
• neynar_user_by_verification - Find the user that verified a given Ethereum address
• neynar_user_search - Search users by name/username
• neynar_power_users - List Farcaster power users

Follows

• neynar_user_followers - List a user's followers
• neynar_user_following - List users a given user follows

Casts

• neynar_casts_by_fid - Recent casts authored by a user
• neynar_cast_by_hash - Get a single cast by hash or Warpcast URL
• neynar_casts_bulk - Fetch many casts by hash in one call
• neynar_cast_search - Full-text search across casts
• neynar_conversation - Full reply thread for a cast

Feeds

• neynar_feed - Get a Farcaster feed (following / filter / channel)
• neynar_trending_feed - Trending casts (globally or in a channel)

Channels

• neynar_channel - Channel details
• neynar_channel_search - Search channels by name
• neynar_channel_followers - Followers of a channel

Reactions

• neynar_cast_reactions - Likes / recasts on a cast
• neynar_user_reactions - Reactions made by a user

Notifications

• neynar_user_notifications - Notifications for a user (mentions, replies, follows, likes, recasts)

Signer (writes)

Writes need a signer — a Farcaster account that has authorized your Neynar app to act on its behalf. The workflow is:

1. Run neynar_signer_create → response contains signer_uuid and a signer_approval_url.
2. Open signer_approval_url in Warpcast and approve the signer for your Farcaster account.
3. Poll neynar_signer_status until status === "approved".
4. Use the signer_uuid in any write operation below.

The same signer_uuid can be reused across runs until revoked.

• neynar_signer_create - Provision a new managed signer (returns approval URL)
• neynar_signer_status - Check signer status

Write — Casts

• neynar_publish_cast - Publish a new cast (optionally as reply, in a channel, with embeds)
• neynar_delete_cast - Delete a cast by hash

Write — Reactions

• neynar_react_to_cast - Like or recast a cast
• neynar_remove_reaction - Remove a like / recast

Write — Follows

• neynar_follow_user - Follow one or more users
• neynar_unfollow_user - Unfollow one or more users
• neynar_channel_follow - Follow a channel
• neynar_channel_unfollow - Unfollow a channel

Common Inputs

Output

Notes

• Category: tools
• Type: neynar
• BYOK only. The platform does not hold a Neynar API key.
• Free starter tier covers development; paid plans for production / commercial workloads.
• Write operations require a signer — see the Signer (writes) section above. The signer flow is a one-time setup per Farcaster account; the same signer_uuid can be reused across many workflows.
• A revoked signer (user disabled it in Warpcast) will reject writes — re-run Create Signer and re-approve.