Neynar provides three options for adding sign-in with Farcaster in your app to create maximum flexibility for developers. In this guide, we’ll break down all the methods, and by the end of this guide, you’ll know which option to use based on your needs.

The three options are:

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Neynar Sponsored Signers: Sign in with Neynar (SIWN)

[Recommended for most developers]

When utilizing Neynar sponsored signers, developers are relieved from building any part of auth or signer flows. SIWN is plug-and-play on the web and React Native. See SIWN: Connect Farcaster Accounts on how to start using it.

Benefits of using Neynar-sponsored signers:

• Cost-effective for users. Users don’t pay gas for any signers they create
• 35k+ users only need to authenticate their profile in one step to onboard on to their app, and the number is increasing daily
• Users retain the ability to revoke a signer from any app at any time at app.neynar.com
• No auth buildout, or signer management is required for developers

Tradeoff:

• Auth flow UI cannot be customized fully, see Managed Signers option below if that is a requirement

This is the simplest approach to add Farcaster read+write auth to your product and is recommended for most developers.

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Neynar Sponsored signers: backend only

Neynar-managed signers empower developers to maintain their branding and direct control over their signers while delegating secure storage and signing to Neynar. With Neynar-managed signers, you generate the signers yourself but register them with Neynar. This lets you showcase your branding on the Warpcast connect page and utilize Neynar’s features.

Benefits of using Neynar-managed signers:

• Custom branding on the Warpcast Connect page, sponsoring signers for users is still possible
• Custom UI on user auth flow
• Full access to Neynar’s APIs, including features such as signer lookup, registering signed keys, publishing messages, and more
• No signer management or secure storage needed, Neynar does that for you
• Still possible to Sponsor signers
• No need to learn how to do message construction for different message types, Neynar submits messages for you
• You can look at the available APIs and learn how to use managed signers.

Tradeoffs of this approach are:

• need to build your own auth flow if you don’t want your users to create a new signer every time they log into your app

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Developer Managed signers

Developer-managed signers enable developers to retain custody of the signers while utilizing Neynar to interface with the protocol efficiently.

Neynar helps with developer-managed signers in the following ways:

• Seamless User Interaction: Neynar streamlines the process by providing a URL from the Farcaster client (currently Warpcast only). This enables developers to deep-link users directly to the app for signer approval. This ensures a smooth and intuitive user experience.
• Real time status monitoring : Developers can utilize Neynar to poll the status of a signer periodically. This lets you check whether the user has signed in with a valid signer in real-time.
• Efficient Message Publication: Leverage Neynar’s optimizations to publish messages to the right hubs across the network. Here’s an API that lets you do this easily. Unlike doing this on your own, Neynar runs a network of Hubs with fallbacks ensuring that each publish event has the highest chances of success.

Developer-managed signers empower developers with greater control and flexibility over signer custody. At the same time, Neynar provides essential tools and optimizations to improve message publication and reliability.

The tradeoffs of this approach are needing to:

• handle secure storage of signers on their end
• signing messages themselves before submitting them to the Neynar APIs
• building your own auth flow if you don’t want your users to create a new signer every time they log into your app
• pay for signers yourself or deal with onboarding friction since users pay for their signer creation

This is the most complex way of adding Farcaster read+write to your product and is not recommended unless you want to manage everything regarding signers.