---
title: "By FID or cast"
method: GET
path: "/v1/reactionById"
tags: ["Reactions"]
---

# By FID or cast

`GET /v1/reactionById`

Lookup a reaction by its FID or cast.

## Query parameters

- `fid` integer, required
- `target_fid` integer, required
- `target_hash` string, required
- `reaction_type` 'Like' | 'Recast', required — Type of interaction a user can have with content on the Farcaster network. - Like: Express appreciation for the target content. Similar to "likes" or "favorites" on other platforms. - Recast: Share the target content with the user's followers, similar to a "retweet" or "reblog". Helps increase content visibility.

## Response `200`

The requested Reaction.

- Reaction
  - `hash` string, required
  - `hashScheme` 'HASH_SCHEME_BLAKE3', required — Type of hashing scheme used to produce a digest of MessageData. - HASH_SCHEME_BLAKE3: Default scheme for hashing MessageData
  - `signature` string, byte, required
  - `signatureScheme` 'SIGNATURE_SCHEME_ED25519' | 'SIGNATURE_SCHEME_EIP712', required — Type of signature scheme used to sign the Message hash - SIGNATURE_SCHEME_ED25519: Ed25519 signature (default) - SIGNATURE_SCHEME_EIP712: ECDSA signature using EIP-712 scheme
  - `signer` string, required
  - `data` object, required — Common properties shared by all Farcaster message types. These properties provide essential metadata about the message's origin, timing, and network context.
    - `type` 'MESSAGE_TYPE_CAST_ADD' | 'MESSAGE_TYPE_CAST_REMOVE' | 'MESSAGE_TYPE_REACTION_ADD' | 'MESSAGE_TYPE_REACTION_REMOVE' | 'MESSAGE_TYPE_LINK_ADD' | 'MESSAGE_TYPE_LINK_REMOVE' | 'MESSAGE_TYPE_VERIFICATION_ADD_ETH_ADDRESS' | 'MESSAGE_TYPE_VERIFICATION_REMOVE' | 'MESSAGE_TYPE_USER_DATA_ADD' | 'MESSAGE_TYPE_USERNAME_PROOF' | 'MESSAGE_TYPE_FRAME_ACTION', required — Type of the MessageBody. - MESSAGE_TYPE_CAST_ADD: Add a new Cast - MESSAGE_TYPE_CAST_REMOVE: Remove an existing Cast - MESSAGE_TYPE_REACTION_ADD: Add a Reaction to a Cast - MESSAGE_TYPE_REACTION_REMOVE: Remove a Reaction from a Cast - MESSAGE_TYPE_LINK_ADD: Add a new Link - MESSAGE_TYPE_LINK_REMOVE: Remove an existing Link - MESSAGE_TYPE_VERIFICATION_ADD_ETH_ADDRESS: Add a Verification of an Ethereum Address - MESSAGE_TYPE_VERIFICATION_REMOVE: Remove a Verification - MESSAGE_TYPE_USER_DATA_ADD: Add metadata about a user - MESSAGE_TYPE_USERNAME_PROOF: Add or replace a username proof - MESSAGE_TYPE_FRAME_ACTION: A Farcaster Frame action
    - `fid` integer, required — The unique identifier (FID) of the user who created this message. FIDs are assigned sequentially when users register on the network and cannot be changed.
    - `timestamp` integer, required — Seconds since Farcaster Epoch (2021-01-01T00:00:00Z). Used to order messages chronologically and determine the most recent state. Must be within 10 minutes of the current time when the message is created.
    - `network` 'FARCASTER_NETWORK_MAINNET' | 'FARCASTER_NETWORK_TESTNET' | 'FARCASTER_NETWORK_DEVNET', required — Farcaster network the message is intended for. - FARCASTER_NETWORK_MAINNET: Public primary network - FARCASTER_NETWORK_TESTNET: Public test network - FARCASTER_NETWORK_DEVNET: Private test network
    - `reactionBody` ReactionBody, required — Specifies the details of a reaction to content on Farcaster. A reaction must specify its type (like/recast) and either a target cast ID or URL to react to. Only one target (either castId or URL) should be specified per reaction.
      - `type` 'Like' | 'Recast', required — Type of interaction a user can have with content on the Farcaster network. - Like: Express appreciation for the target content. Similar to "likes" or "favorites" on other platforms. - Recast: Share the target content with the user's followers, similar to a "retweet" or "reblog". Helps increase content visibility.
      - `targetCastId` CastId — A unique identifier for a cast (post) in the Farcaster network, consisting of the creator's FID and a hash of the cast's content. This combination ensures global uniqueness across all casts.
        - `fid` integer, required — The Farcaster ID (FID) of the user who created the cast. Required to uniquely identify the cast's author in the network.
        - `hash` string, required — A unique hash that identifies a specific cast within the creator's posts. Generated using HASH_SCHEME_BLAKE3 of the cast's content.
      - `targetUrl` string — The URL being reacted to. Used when reacting to external content or when the cast ID is not available.

## Other responses

- `default` — An unexpected error response.

---

[API](https://skmtc.dev/neynar/apis/neynar-api.md) · [All operations](https://skmtc.dev/neynar/apis/neynar-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/neynar/neynar-api/revisions/dbb91bfb0d1a/schema)