neynar

name	neynar
description	Interact with Farcaster via Neynar API. Use when the user wants to read Farcaster feeds, look up users, post casts, search content, or interact with the Farcaster social protocol. Requires NEYNAR_API_KEY.
metadata	{"thinkfleetbot":{"emoji":"🟪","homepage":"https://neynar.com","requires":{"bins":["curl","jq"]}}}

Neynar (Farcaster API)

Interact with the Farcaster decentralized social protocol via Neynar's API.

Quick Start

Setup

1. Get an API key from dev.neynar.com
2. Create config:

mkdir -p ~/.thinkfleet/skills/neynar
cat > ~/.thinkfleet/skills/neynar/config.json << 'EOF'
{
  "apiKey": "YOUR_NEYNAR_API_KEY",
  "signerUuid": "YOUR_SIGNER_UUID"
}
EOF

Note: signerUuid is only required for posting casts. Get one via Neynar's signer management.

Verify Setup

scripts/neynar.sh user dwr.eth

Core Concepts

• FID — Farcaster ID, a permanent numeric identifier for each user
• Cast — A post on Farcaster (like a tweet)
• Channel — Topic-based feeds (like subreddits)
• Frame — Interactive mini-apps embedded in casts

Usage

User Lookup

# By username
scripts/neynar.sh user vitalik.eth

# By FID
scripts/neynar.sh user --fid 5650

# Multiple users
scripts/neynar.sh users dwr.eth,v,jessepollak

Read Feed

# User's casts
scripts/neynar.sh feed --user dwr.eth

# Channel feed
scripts/neynar.sh feed --channel base

# Trending feed
scripts/neynar.sh feed --trending

# Following feed (requires signer)
scripts/neynar.sh feed --following

Search

# Search casts
scripts/neynar.sh search "ethereum"

# Search users
scripts/neynar.sh search-users "vitalik"

# Search in channel
scripts/neynar.sh search "onchain summer" --channel base

Get Cast

# By hash
scripts/neynar.sh cast 0x1234abcd...

# By URL
scripts/neynar.sh cast "https://warpcast.com/dwr.eth/0x1234"

Post Cast (requires signer)

# Simple cast
scripts/neynar.sh post "gm farcaster"

# Reply to cast
scripts/neynar.sh post "great point!" --reply-to 0x1234abcd

# Cast in channel
scripts/neynar.sh post "hello base" --channel base

# Cast with embed
scripts/neynar.sh post "check this out" --embed "https://example.com"

Reactions

# Like a cast
scripts/neynar.sh like 0x1234abcd

# Recast
scripts/neynar.sh recast 0x1234abcd

Follow/Unfollow

scripts/neynar.sh follow dwr.eth
scripts/neynar.sh unfollow dwr.eth

API Reference

Endpoints Used

Action	Endpoint	Auth
User lookup	GET /v2/farcaster/user/by_username	API key
User by FID	GET /v2/farcaster/user/bulk	API key
User feed	GET /v2/farcaster/feed/user/casts	API key
Channel feed	GET /v2/farcaster/feed/channels	API key
Trending	GET /v2/farcaster/feed/trending	API key
Search casts	GET /v2/farcaster/cast/search	API key
Get cast	GET /v2/farcaster/cast	API key
Post cast	POST /v2/farcaster/cast	API key + Signer
React	POST /v2/farcaster/reaction	API key + Signer
Follow	POST /v2/farcaster/user/follow	API key + Signer

Response Format

All responses are JSON. The script extracts key fields for readability:

{
  "user": {
    "fid": 3,
    "username": "dwr.eth",
    "display_name": "Dan Romero",
    "follower_count": 450000,
    "following_count": 2800,
    "verified_addresses": ["0x..."]
  }
}

Common Patterns

Monitor a Channel

# Get latest casts from /base channel
scripts/neynar.sh feed --channel base --limit 20

Find Active Users

# Search for users by keyword
scripts/neynar.sh search-users "ethereum developer"

Cross-Post from Twitter

# Post same content to Farcaster
scripts/neynar.sh post "gm, just shipped a new feature 🚀"

Reply to Mentions

# Get your notifications (requires signer)
scripts/neynar.sh notifications

# Reply to specific cast
scripts/neynar.sh post "thanks!" --reply-to 0xabc123

Error Handling

Error	Cause	Fix
401 Unauthorized	Invalid API key	Check config.json
403 Forbidden	Signer required	Set up signer for write operations
404 Not Found	User/cast doesn't exist	Verify username/hash
429 Rate Limited	Too many requests	Wait and retry

Signer Setup

For write operations (posting, liking, following), you need a signer:

1. Go to dev.neynar.com
2. Create a new signer or use managed signer
3. Add signerUuid to your config

Managed signers are easiest — Neynar handles the key custody.

Rate Limits

• Free tier: 300 requests/minute
• Paid tiers: Higher limits available
• Check X-RateLimit-Remaining header

Best Practices

1. Cache user lookups — FIDs don't change, usernames rarely do
2. Use channels — Better reach than random posting
3. Engage genuinely — Farcaster culture values authenticity
4. Batch requests — Use bulk endpoints when possible
5. Handle rate limits — Implement backoff

Resources

• Neynar Docs: https://docs.neynar.com
• API Reference: https://docs.neynar.com/reference
• Developer Portal: https://dev.neynar.com
• Farcaster Docs: https://docs.farcaster.xyz

Troubleshooting

API Key Not Working

# Verify key works
curl -H "x-api-key: YOUR_KEY" \
  "https://api.neynar.com/v2/farcaster/user/bulk?fids=1"

Signer Issues

• Ensure signer is approved and active
• Check signer permissions match your FID
• Managed signers are simpler than self-hosted

Cast Not Appearing

• Casts propagate in seconds, but indexing may take longer
• Check the cast hash in the response
• Verify on warpcast.com directly