/**
 * Helpers for ERC20-denominated listing fulfillment.
 *
 * When a listing is priced in an ERC20 token instead of the native currency,
 * `transaction.value` is `0` and Seaport pulls the payment from the buyer with
 * `transferFrom`. That only works if the buyer has already approved the spender,
 * so the fulfillment reverts with a bare "execution reverted" when they haven't.
 * These helpers read the payment token and amount out of the API's fulfillment
 * input data so the SDK can check the allowance before spending gas.
 */
/** A `bytes32(0)` conduit key means Seaport transfers directly, with no conduit. */
export declare const ZERO_CONDUIT_KEY: string;
export type Erc20Payment = {
    /** Payment token contract address. */
    token: string;
    /** Total amount the fulfiller owes, in the token's base units. */
    amount: bigint;
};
/**
 * Coerce a value an RPC adapter may return as a bigint, a decimal string, or a
 * number into a bigint. Returns null for anything else.
 */
export declare function toBigInt(value: unknown): bigint | null;
/**
 * Read the ERC20 payment a fulfiller owes from the `inputData` of an OpenSea
 * fulfillment response.
 *
 * Returns null whenever the payment is not a single ERC20 amount we can read
 * with confidence, including native-priced listings and offer fulfillments.
 * Callers must treat null as "no preflight possible" and submit the transaction
 * unchanged, so an unfamiliar response shape can never block a working purchase.
 */
export declare function getErc20Payment(inputData: unknown): Erc20Payment | null;
/**
 * Read the fulfiller's conduit key, which decides who the buyer must approve:
 * the resolved conduit for a non-zero key, or Seaport itself for `bytes32(0)`.
 * Returns null when the response does not carry one.
 */
export declare function getFulfillerConduitKey(inputData: unknown): string | null;
/** Whether a conduit key means "transfer directly from Seaport, no conduit". */
export declare function isZeroConduitKey(conduitKey: string | null): boolean;