Routing Integration Models

Every Relay integration gets the same cross-chain execution layer: deposits, solver-funded fills, tracking, and refunds for unfilled deposits. The choice you make is who routes the swap legs. There are three models, and they are not mutually exclusive — you can start with Relay routing and layer in the others later.

• Relay routing: Relay quotes multiple swap providers and selects the best route. The default, and zero routing work for you.
• Your router as a Relay quote source: your router competes as a candidate inside Relay’s routing. A bespoke integration.
• Your own calldata: you route, Relay executes. Full control, full ownership.

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The three models at a glance

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Relay routing

For each swap leg, Relay runs a meta-aggregation: it quotes multiple swap providers on that chain and selects the best executable route for the trade. You request a quote and execute the returned steps; routing, provider selection, and provider maintenance are Relay’s job. This is where routing improvements accrue to you automatically — new providers, better route selection, and chain expansions apply to your integration without any work on your side. You can see the providers available per chain with the swap sources endpoint, and control provider selection per request with the parameters below.

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Configuring swap sources

Relay routing stays configurable without leaving the model. These optional /quote/v2 parameters control which swap sources participate in a request: Source names come from the swap sources endpoint. Restricting sources narrows the routes Relay can compare, so reach for these when you have a concrete requirement rather than as a default.

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Your router as a Relay quote source

If you run your own router or have preferred liquidity, Relay can onboard it as a quote source: your router constructs its candidate route, and Relay compares it against the other providers and selects the winner for each trade. Your routing participates without replacing Relay’s — when your router has the best route it wins, and when it doesn’t, your users still get the best available one. You keep the execution protections and chain coverage of Relay routing, and your router only needs to cover the chains you care about. Partners run this in production today: their router participates as a restricted quote source in their own trades while Relay retains route selection.

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Your own calldata

If you want full route-selection control, construct the swap yourself and pass the encoded transactions in the quote’s txs array. Relay provides the cross-chain execution layer — deposit handling, the solver-funded fill, tracking, and refunds for unfilled deposits — and your calldata defines what executes. See the call execution guide for the mechanics, including approval ordering and EXACT_INPUT considerations. The tradeoff is ownership: route quality, failed routes, provider relationships, and per-chain maintenance are yours, and routing improvements on Relay’s side don’t reach your users.

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Choosing a model

Start with Relay routing — it is the default for a reason, and the other two models layer on top rather than replace it. Move to a quote-source integration when you have routing or liquidity you want represented without giving up aggregation. Reserve full calldata control for cases where route selection itself is your product.