---
title: Exported types
description: Reference for Result, inference helpers, tagged error helpers, codec types, serialized envelopes, retry context, and Standard Schema types.
---

All public types are imported from `better-result`.

## Result and inference

| Type               | Meaning                                           |
| ------------------ | ------------------------------------------------- |
| `Result<T, E>`     | `Ok<T, E> \| Err<T, E>`                           |
| `Ok<T, E = never>` | success variant class                             |
| `Err<T, E>`        | error variant class                               |
| `InferOk<R>`       | extract the success type from a Result or variant |
| `InferErr<R>`      | extract the error type from a Result or variant   |

```ts
const result = Result.gen(function* () {
  const user = yield* findUser(id);
  return Result.ok(user.name);
});

type Value = InferOk<typeof result>; // string
type Error = InferErr<typeof result>; // FindUserError
```

## Tagged errors

| Type                              | Meaning                                              |
| --------------------------------- | ---------------------------------------------------- |
| `AnyTaggedError`                  | any tagged Error with `_tag` and `toJSON()`          |
| `TaggedErrorClass<Tag>`           | generic class returned by the factory                |
| `TaggedErrorInstance<Tag, Props>` | structural tagged error instance with readonly Props |

## Retry context

| Type                | Fields                                            |
| ------------------- | ------------------------------------------------- |
| `TryContext`        | `attempt: number` (one-based)                     |
| `TryPromiseContext` | `attempt: number`, optional `signal: AbortSignal` |

Retry config itself is inferred from `Result.tryPromise`; it is not exported as a named type.

## Serialized envelopes

| Type                     | Shape                                 |
| ------------------------ | ------------------------------------- |
| `SerializedOk<T>`        | `{ status: "ok"; value: T }`          |
| `SerializedErr<E>`       | `{ status: "error"; error: E }`       |
| `SerializedResult<T, E>` | `SerializedOk<T> \| SerializedErr<E>` |

These describe wire envelopes, not proof of validation. Use `Result.codec` at untrusted boundaries.

## Codec types

| Type                     | Meaning                                         |
| ------------------------ | ----------------------------------------------- |
| `ResultCodecConfig<...>` | four schemas for serialize/deserialize × ok/err |
| `ResultCodec<...>`       | safe and unsafe codec operations                |
| `ResultCodecIssue`       | Standard Schema validation issue alias          |

## Standard Schema types

| Type                              | Meaning                             |
| --------------------------------- | ----------------------------------- |
| `StandardSchemaV1<Input, Output>` | supported Standard Schema interface |
| `StandardSchemaInput<S>`          | infer schema input                  |
| `StandardSchemaOutput<S>`         | infer schema output                 |
| `StandardSchemaIssue`             | one validation issue                |
| `StandardSchemaPathSegment`       | validation path property wrapper    |
| `StandardSchemaResult<Output>`    | schema success-or-issues result     |

Prefer your schema library's public types in application code. These exports are useful for generic codec tooling and libraries that integrate directly with better-result.