Post a reaction (like or recast) to a given cast \
(In order to post a reaction `signer_uuid` must be approved)


Post a reaction

The unique identifier of a farcaster user (unsigned integer)

An Idempotency key is a unique identifier for the request.
**Note:** 
1) This is used to prevent duplicate requests. Use the same idem key on retry attempts.
2) This should be a unique identifier for each request.
3) Recommended format is a 16-character string generated by the developer at the time of making this request.


UUID of the signer.
`signer_uuid` is paired with API key, can't use a `uuid` made with a different API key.


ApiKeyAuth

Neynar

Overview

Getting Started

Start developing on Farcaster with Neynar and AI enabled Cursor

Cursor and MCP setup

Set up Neynar with Cursor and MCP server

Supercharge Sign In with Ethereum and/or Solana in your app with Farcaster profile and social graph data

Supercharge Crypto Sign-in

Supercharge EVM & Solana Sign-in

Find Farcaster user profile based on ethereum address

User by Wallet Address

Show good recommendations when users search for Farcaster users in your app

Username Search

Hide users and their activity based on user or developer preference

Mutes, Blocks, and Bans

Create a v2 Farcaster mini app in less than 60 seconds

Create Mini App in < 60s

Create Farcaster Mini App (v2 frame) in < 60s

Update any JavaScript web app to be a Farcaster mini app

Convert Web App to Mini App

Convert a Web App to a Farcaster Mini App

This guide walks you through a simple setup for enabling notifications for your mini app

Send Notifications to Mini App Users

Neynar's API now supports HTML metadata for mini apps (prev. called Frames) and catalogs, providing rich information about embedded content. This feature allows you to access Open Graph (OG) data and oEmbed information for frames and catalogs, similar to how it works with casts.

Mini App Metadata

HTML & OpenGraph Metadata in Mini Apps

Convert Warpcast URL into full cast data from Farcaster network through Neynar

Warpcast URLs

Fetch stream of casts with Farcaster hubs

Cast Stream

Archive Casts

Get notified when someone tags your bot in a cast

Listen for @bot Mentions

Agents prompt transactions to humans with Farcaster frames

Make Agents Prompt Transactions

Show casts from a Farcaster channel with Neynar

Channel Feeds

Fetch & Display Farcaster Feeds with Neynar API

Show Farcaster casts that have attachments with Neynar

Casts by Embed in Farcaster

A guide on how to get feed from the Feed API using fid, fids, and parent_url.

How to Use the Neynar Feed API

Understand the differences between the various ways to manage signers and pick the right one for your app

Choose the Right Signer

Add "like" and "recast" reactions on Farcaster casts

Like & Recast

Write casts to a Farcaster channel with Neynar

Write Casts to Channel

Check for quality users using Neynar's user score

Neynar User Score

Neynar APIs rank high quality casts higher

Rank High Quality Conversations

Pick between pulling or pushing data in the format that works for you

Choose Among Data Products

This guide will look at creating a Farcaster client using Next.js and the Neynar React SDK.

React client

User Neynar dev portal to set up webhooks for your app

Webhooks in Dashboard

Neynar webhooks are a way to receive real-time updates about events on the Farcaster protocol. You can use webhooks to build integrations that respond to events on the protocol, such as when a user creates a cast or when a user updates their profile.

Programmatic Webhooks

This guide highlights the steps to verify incoming webhooks using signatures

Verify Webhooks

Fetch notifications for any Farcaster user

Notifications for FID

Show notifications from a specific channel for a Farcaster user

Notifications in Channel

This guide provides a step-by-step process to deploy a fungible token on the Base network using Neynar's API. The deployment process is simplified to a single API call, eliminating the need for developers to write Solidity code or handle on-chain transaction signing. Neynar covers the on-chain deployment fees and assigns the specified owner address as the token owner.

Deploy Base Token with 1 API Call

Deploy a Token on Base with 1 API Call

This guide provides a comprehensive overview of how to use the Neynar API to fetch relevant holders of a fungible token.

Relevant Holders for Coins

This guide provides a step-by-step approach to fetching token balances for a user using their Farcaster FID via the Neynar API.

User Balances Directly with FID

In this guide, we’ll make a webhook which will send a DC to the user based on any action they perform on Farcaster! For this guide, I'll send direct casts to people whose casts include a specific keyword.

Webhooks with DCs

Fetch data about a user's storage allocation on Farcaster network with Neynar

Storage Units Allocation

Farcaster Actions Spec

Get an addresses' connected fid on-chain.

ETH Address FID Contract

Get user quality score for an address connected to a Farcaster profile.

Address User Score Contract

Search for specific messages and debug Farcaster network health

Farcaster event propagation

Explore Event Propagation on Farcaster

Finding Hypersub subscriptions on Social Token Protocol (STP) using Neynar

Find Hypersub subscriptions

Find User Subscriptions with Neynar Hypersub

Building blocks for developing on Farcaster protocol with Neynar infrastructure

Developer Ecosystem

Quickstart

Rate limits are set per subscription plan

Rate Limits

Compute Units Pricing

Deploy fungible

Easily call Neynar APIs with our nodejs sdk

Getting Started with Neynar NodeJS SDK

Easily call Neynar APIs with our Rust SDK

Overview

Farcaster

Onchain

Farcaster Hub API

Neynar SDK

Github

Post a reaction

Authorizations

Body

Response

Overview

Farcaster

Onchain

Farcaster Hub API

Neynar SDK

Github

​Related tutorial: Like and recast

Authorizations

Body

Response

Related tutorial: Like and recast