import { TypeFromCodec } from '@cloudflare/util-en-garde';
export declare const CaptchaChallenge: import("@cloudflare/util-en-garde").ObjectCodec<{
    challenge_required: import("@cloudflare/util-en-garde").Codec<import("io-ts").BooleanC>;
    key: import("@cloudflare/util-en-garde").Codec<import("io-ts").StringC>;
    challenge_provider: import("@cloudflare/util-en-garde").Codec<import("io-ts").StringC>;
    captcha_challenge_jwt: import("@cloudflare/util-en-garde").Codec<import("io-ts").UnionC<[import("@cloudflare/util-en-garde").Codec<import("io-ts").StringC>, import("io-ts").UndefinedC]>>;
}>;
export type CaptchaChallenge = TypeFromCodec<typeof CaptchaChallenge>;