feat(transaction-pay): add Across strategy support by pedronfigueiredo · Pull Request #7886 · MetaMask/core

pedronfigueiredo · 2026-02-10T11:23:47Z

Explanation

This PR extracts the Across strategy work on top of the provider-fallback baseline.

It adds:

Across strategy wiring (across strategy type + registration)
Across quote retrieval/parsing/normalization
Across submit flow for approval + swap/deposit execution paths
Across-specific types/constants required for compilation
Minimal selection/config hooks to make Across selectable
Changelog entries for transaction-controller and transaction-pay-controller

References

Addresses: https://github.com/MetaMask/MetaMask-planning/issues/6997

Checklist

I've updated the test suite for new or updated code as appropriate
I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
I've communicated my changes to consumers by updating changelogs for packages I've changed
I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

Note

Medium Risk
Introduces a new on-chain submission path and remote API integration (Across) with batching, gas estimation fallbacks, and status polling, which could affect transaction correctness and user funds if misconfigured or edge cases are missed.

Overview
Adds a new Across pay strategy that can be feature-flag enabled/ordered, including a supports gate (cross-chain only by default) and wiring into strategy selection.

Implements Across quote retrieval/normalization (/swap/approval) with slippage + optional MetaMask app-fee params, recipient derivation limited to token transfer calldata, EIP-7702 authorization-list rejection, and gas/fee/dust calculations using shared utilities.

Implements Across execution that submits approval+deposit transactions (batch when needed), maps parent tx types to new perpsAcrossDeposit/predictAcrossDeposit types, collects required transaction IDs, applies buffered/fallback gas estimation, and optionally polls Across /deposit/status for a destination hash. Also refactors common amount/fiat helpers and adds extensive unit tests and changelog entries.

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packages/transaction-pay-controller/src/strategy/across/across-submit.ts

packages/transaction-pay-controller/src/strategy/across/types.ts

packages/transaction-pay-controller/src/strategy/across/across-submit.ts

packages/transaction-pay-controller/src/strategy/across/across-quotes.ts

packages/transaction-pay-controller/src/strategy/across/across-submit.ts

packages/transaction-pay-controller/src/strategy/across/across-quotes.ts

matthewwalsh0 · 2026-02-13T22:48:19Z

packages/transaction-pay-controller/src/utils/gas.ts

+  return getFeatureFlags(messenger).relayFallbackGas;
+}
+
+export async function estimateGasWithBufferOrFallback({


estimateGasLimit?

matthewwalsh0 · 2026-02-13T22:48:34Z

packages/transaction-pay-controller/src/utils/gas.ts

  };
 }

+export function getFallbackGas(messenger: TransactionPayControllerMessenger): {


Should this be in feature-flags.ts?

matthewwalsh0 · 2026-02-13T22:49:54Z

packages/transaction-pay-controller/src/utils/gas.ts

+    error = caughtError;
+  }
+
+  const fallbackGas = getFallbackGas(messenger);


Debatable whether we should have fallback gas or throw as it implies the transaction would revert?

fallback is now option but off by default

matthewwalsh0 · 2026-02-13T22:51:46Z

packages/transaction-pay-controller/src/utils/feature-flags.ts

+  across?: PayStrategyConfigRaw;
+  relay?: {
+    enabled?: boolean;
+    relayQuoteUrl?: string;


Is this redundant as we already have the top level value?

matthewwalsh0 · 2026-02-13T22:52:54Z

packages/transaction-pay-controller/src/utils/feature-flags.ts

  slippage: number;
 };

+export type PayStrategyConfigRaw = {


Should this be AcrossConfig?

matthewwalsh0 · 2026-02-13T23:25:24Z

packages/transaction-pay-controller/src/strategy/across/across-quotes.ts

+    messenger,
+  });
+
+  const max = calculateGasCost({


We also need gas station support here, but can do that in a future PR and re-use the Relay logic.

added a ticket for this

matthewwalsh0 · 2026-02-13T23:32:15Z

packages/transaction-pay-controller/src/strategy/across/across-quotes.ts

+  request: QuoteRequest,
+): Promise<TransactionPayQuote<AcrossQuote>['fees']['sourceNetwork']> {
+  const { from } = request;
+  const { swapTx } = quote;


Do we also need to include gas cost of approvalTxns?

matthewwalsh0 · 2026-02-13T23:34:19Z

packages/transaction-pay-controller/src/strategy/across/across-submit.ts

+  const chainId = toHex(params.chainId);
+  const value = toHex(params.value ?? '0x0');
+
+  const gas = await estimateGasWithBuffer(


We don't want to duplicate the gas logic again, but store the gas limits in the quote to use during submit, so we know the network fees will match.

matthewwalsh0 · 2026-02-13T23:34:50Z

packages/transaction-pay-controller/src/strategy/across/across-submit.ts

+    data: params.data,
+    from,
+    gas: toHex(gas),
+    maxFeePerGas: normalizeOptionalHex(params.maxFeePerGas),


Can they not return gas fee properties?

not sure I understand the question here, it's simply normalising to hex if needed.

matthewwalsh0 · 2026-02-13T23:37:05Z

packages/transaction-pay-controller/src/strategy/across/across-submit.ts

+  }
+
+  await Promise.all(
+    transactionIds.map((txId) => waitForTransactionConfirmed(txId, messenger)),


We're waiting for the deposit transactions to succeed, but we also need to poll the Across API to verify the status of their transactions on the target chain.

Looks like /deposit/status?