/**
 * Helpers for receiving and verifying Notion webhook deliveries.
 *
 * Event signatures use HMAC-SHA256 with the subscription's verification
 * token. The `X-Notion-Signature` header contains `sha256=<hex>`.
 * Pass the raw body as received. Parsing and re-serializing JSON can change
 * its bytes and invalidate the signature.
 *
 * The helpers use `globalThis.crypto.subtle` when available, then fall
 * back to the Web Crypto API in Node's crypto module.
 */
export type VerifyWebhookSignatureArgs = {
    /**
     * The raw HTTP request body, before any parsing.
     * Pass a string for text bodies or a Uint8Array/Buffer for binary-safe
     * access. Re-serialized JSON will not verify.
     */
    body: string | Uint8Array;
    /**
     * The value of the `X-Notion-Signature` request header. Verification
     * fails (returns false) if this is missing or malformed.
     */
    signature: string | null | undefined;
    /**
     * The verification token configured for this webhook subscription
     * (returned by Notion when the subscription was created and surfaced
     * during the initial handshake).
     */
    verificationToken: string;
};
/**
 * Verify that a webhook delivery came from Notion and has not been
 * tampered with.
 *
 * Returns `true` if the signature matches HMAC-SHA256 of the body using
 * the verification token. Returns `false` for a missing or malformed
 * signature. Crypto errors may throw.
 */
export declare function verifyWebhookSignature(args: VerifyWebhookSignatureArgs): Promise<boolean>;
/**
 * Compute the value Notion would send in `X-Notion-Signature` for a
 * given body and verification token. Use this to test webhook handlers
 * without a live subscription.
 */
export declare function signWebhookPayload(args: {
    body: string | Uint8Array;
    verificationToken: string;
}): Promise<string>;
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