Multichain Authentication (SIWX): How and why to enable it in your app
Building multichain applications often involves significant friction — developers end up managing fragmented authentication flows for different ecosystems, each with its own logic, libraries, and maintenance overhead. Multichain Authentication (SIWX) solves this by providing a unified, secure way for users to sign in across various networks. As an authentication method powered by Reown, SIWX extends the message-based security of Sign-In with Ethereum (SIWE) to a multichain environment, so teams can support Ethereum, Solana, Bitcoin, and more from a single integration.
Why add Multichain Authentication (SIWX) to your app?
Support multiple networks without fragmentation
SIWX enables seamless support across Ethereum, Solana, Bitcoin, and more. This allows developers to unlock access to hundreds of trusted wallets and millions of users across the financial internet without building or maintaining separate authentication paths per chain.
Consolidate your authentication infrastructure
By integrating SIWX, teams can replace multiple chain-specific authentication implementations with one flexible flow that supports various login preferences. This eliminates complexity and lets builders ship faster.
Enable Travel Rule compliance by default
Reown infrastructure includes built-in verification APIs that ensure global compliance without breaking the user experience. Using SIWX allows apps to meet Travel Rule requirements and track regions seamlessly as part of the standard authentication process.
Learn more about SIWX and the Travel Rule →
Who should add Multichain Authentication (SIWX) to their apps?
Multichain blockchain games
SIWX is perfect for developing blockchain games that operate across different ecosystems. Using SIWX, you can provide players with a consistent cross-chain experience. This allows players to move assets or progress across chains like Ethereum and Solana using a single, frictionless login — without being prompted to re-authenticate per network.
Multichain decentralised exchanges
DEXs can leverage SIWX to offer users a streamlined onboarding experience where they can pay, swap, or deposit directly in-app across multiple chains. If you're building a DeFi app, this allows you to reduce friction and ensure every transaction is secured by the underlying WalletConnect protocol.
Multichain marketplaces
Marketplaces benefit from SIWX's built-in session analytics that surface user behaviour across different networks. This helps blockchain marketplace developers to optimise the onboarding and retention of users who interact with assets on various ecosystems.
Multichain prediction markets
For prediction markets requiring high security and control, SIWX provides a trusted authentication infrastructure powering significant cross-chain volume. It allows teams to launch embedded onchain offerings with cross-ecosystem flexibility for their users.
How does Multichain Authentication (SIWX) work?
Multichain Authentication (SIWX) is a message-based authentication standard that allows users to prove ownership of their wallet across different blockchain ecosystems using a single interface. When integrated via the Reown SDK, SIWX handles the full process of creating, signing, and verifying authentication messages.
The Reown SDK abstracts the differences between chain signature formats — EVM, Solana, Bitcoin, and others — providing a unified "Sign-In" experience. It generates a standardised message that the user signs with their wallet; the app then verifies this signature to establish a secure, authenticated session. This replaces manual, chain-specific implementations with a single integration that combines login and session insights.
What to consider when you add Multichain Authentication (SIWX) to your app
Compliance
When choosing an authentication solution, it is vital to consider how it handles global regulations. SIWX via Reown offers Travel Rule compliance by default, using verification APIs to ensure teams meet requirements without sacrificing user experience. This is particularly important for apps operating across jurisdictions or handling regulated financial activity.
Security
Developers should ensure their chosen authentication method provides a cryptographically sound way for users to verify wallet ownership. SIWX provides this foundation — builders can integrate login with fewer steps while maintaining the level of control that institutional-grade applications require.
Most important features
Consider which features your authentication layer needs to support beyond basic login: multichain wallet support, session persistence, signature verification utilities, and analytics. SIWX via Reown includes all of these out of the box, reducing the number of additional libraries or services your team needs to integrate separately.
User experience
A primary consideration is end-user friction. SIWX provides a consistent UX across all supported chains — users can connect with hundreds of wallets without switching apps or moving assets, resulting in faster, lower-friction onboarding.
Before you add Multichain Authentication (SIWX) to your app
Create your Reown project
Set up a project in the Reown dashboard to obtain your Project ID. This is required to authenticate your app with the Reown network and begin using any Reown SDK features.
Install the Reown SDK
Add the Reown SDK to your project using your framework's package manager. The SDK supports React, Next.js, Vue, and other common frontend frameworks. Full installation instructions are available in the Reown docs.
Prepare your backend for signature verification
SIWX authentication requires a server-side verification step. Before integrating the frontend flow, ensure your backend is set up to receive, parse, and validate signed messages from the SDK. Refer to the SIWX documentation for the expected message format and verification utilities.
How to integrate Multichain Authentication (SIWX) into your app: a step-by-step guide
Follow these steps to implement Multichain Authentication using the Reown SDK.
Step 1: Initialise the SDK
Configure the Reown SDK within your application environment. Set your Project ID from the Reown dashboard and define the metadata for your app — including name, description, URL, and icon. This ensures a secure, identifiable connection between your app and the user's wallet.
Step 2: Configure the SIWX provider
Set up the SIWX provider within your app's configuration. This defines the authentication parameters: the statement the user will sign, the domain they are authenticating to, and the chains you want to support. Configuring the domain correctly is essential for preventing phishing attacks. Full configuration options are covered in the SIWX docs.
Step 3: Implement the login flow
Integrate the authentication trigger into your UI. When a user initiates login, the SDK will generate the SIWX message request and prompt the user to select their preferred wallet and sign the authentication message — across any supported network, within the same modal.
Step 4: Verify the signature on your backend
Once the user signs the message, send the signature to your backend for verification. The Reown SDK provides utility functions to validate the signature against the message and address, confirming the session is authentic. This step is what establishes the authenticated session on your server. See the verification guide in the docs for implementation details.
Why Reown is the best solution for Multichain Authentication
Native multichain support out of the box
Reown handles the complexity of different chain signature formats — EVM, Solana, Bitcoin, and others — so your team doesn't have to. Where SIWE (Sign-In with Ethereum) is limited to the Ethereum ecosystem, SIWX via Reown supports the full multichain landscape within a single integration and a single user-facing modal.
Built-in Travel Rule compliance
Reown is one of the only authentication solutions with Travel Rule compliance built into the standard flow. Verification APIs are included by default, so teams don't need to bolt on external compliance services or build custom verification pipelines to meet regulatory requirements.
Fewer integration steps, production-ready infrastructure
The Reown SDK is designed to minimise the time between installation and a working authentication flow. Signature creation, message formatting, chain-specific handling, and session management are all handled by the SDK — leaving teams to focus on their product, not authentication infrastructure.
Unified session analytics
Reown surfaces session data and wallet behaviour through the Reown dashboard, giving product teams visibility into how users authenticate, which chains they connect from, and where drop-off occurs. This removes the need for separate analytics tooling to understand your authentication funnel.
Authenticate any user, crosschain, seamlessly with Reown
By integrating Multichain Authentication (SIWX), you've removed one of the most common sources of friction in multichain app development — and given your users a consistent, secure login experience regardless of which chain they're on.
Reown provides the infrastructure to keep scaling: from SIWX authentication to in-app payments, onramp, and smart accounts, the same SDK covers the full user journey. Get started or explore what's next in the Reown dashboard.
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