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
Adds a new transaction submission path (including batched approvals and on-chain gas estimation/fallback) and new transaction types, which could impact how pay transactions are created and tracked if misconfigured.

Overview
Adds an Across-based pay strategy to transaction-pay-controller, including quote fetching/normalization and a submission flow that can execute approval + deposit (batched) or deposit-only transactions and optionally poll Across for completion.

Extends configuration and utilities to support this: introduces TransactionPayStrategy.Across, feature-flag-driven payStrategies config (incl. default Across API base), validated optional metaMaskFee params, shared amounts helpers, and a new estimateGasLimitWithBufferOrFallback helper used by Across; RelayStrategy now has an explicit supports() gate.

Updates transaction-controller transaction typing with perpsAcrossDeposit/predictAcrossDeposit for attribution, and adds comprehensive tests plus 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?