Farcaster Hub API
HTTP API for Farcaster, the decentralized social protocol. Hubs are nodes that store and serve Farcaster protocol data (casts/posts, reactions, follows, user profiles). The HTTP API provides access to social graph data, user casts, channels, and Frames interactions. Neynar provides a managed Farcaster API as an alternative to running your own Hub.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Protocol is decentralized and open source. Write operations require on-chain Ed25519 Signer — strong cryptographic security. Self-hosted deployments manage their own TLS and security.
⚡ Reliability
Best When
You're building web3-native social applications or research tools on Farcaster and need access to the decentralized social graph.
Avoid When
You need a mainstream social platform with broad user reach — Farcaster's user base is crypto-native and smaller than Twitter/Reddit.
Use Cases
- • Fetch user casts (posts), reactions, and follower graphs for Farcaster users to build social analytics agents
- • Monitor specific Farcaster channels (topics) for new posts to power agent content monitoring and response workflows
- • Query Farcaster user FIDs (Farcaster IDs), ENS names, and on-chain verified addresses for identity resolution in web3 agent pipelines
- • Access Frames interaction data (mini-app responses within Farcaster) for agent-driven social application analytics
- • Build decentralized social agents that post to Farcaster, reply to casts, or manage follows via Signer API
Not For
- • Teams that need hosted managed API without running infrastructure — use Neynar API (neynar.com) as a hosted Farcaster API
- • Non-web3 social use cases — Farcaster user base is crypto-native and much smaller than Twitter/X
- • Real-time high-throughput indexing — self-hosted Hubs require significant storage and sync time for full Farcaster history
Interface
Authentication
Public Hubs have no auth for read operations. Neynar (managed Farcaster API) uses API key. Write operations (posting casts) require a Farcaster Signer — an Ed25519 key pair approved by the user's on-chain account. Self-hosted Hubs require no auth.
Pricing
Core protocol is open source (MIT). For managed API without running infrastructure, use Neynar (neynar.com) which has its own pricing. Most agents use Neynar for simplicity.
Agent Metadata
Known Gotchas
- ⚠ Write operations require a Farcaster Signer (Ed25519 key pair) approved on-chain via the user's Farcaster account — agents cannot post without a valid Signer
- ⚠ Most agents use Neynar (neynar.com) instead of the raw Hub API because Neynar handles Hub infrastructure, Signer management, and provides cleaner REST endpoints
- ⚠ Farcaster IDs (FIDs) are integers, not usernames — username/ENS resolution requires a separate lookup before querying by FID
- ⚠ Hub data may lag 1-10 seconds behind the network depending on Hub sync status — self-hosted Hubs require monitoring sync health
- ⚠ Frames (interactive mini-apps within casts) use a separate Frames API with different schemas — don't confuse with basic cast API
- ⚠ Channel data (topics) uses hash-based IDs, not human-readable names — resolve channel hash to name via lookup API
- ⚠ Self-hosting a full Hub requires syncing the entire Farcaster history (100s of GB) — initial sync takes hours to days
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Farcaster Hub API.
Scores are editorial opinions as of 2026-03-06.