---
title: Transport API
description: Reference for the browser-safe application transport consumed by DomainKit React.
sidebar:
  label: Transport API
seo:
  title: DomainKit application transport API reference
---

`Transport` is a host-facing contract, not a provider client. Implement it on the server, authorize
each method as a product operation, and give `DomainKit.Root` a layer that calls your authenticated
endpoints.

## Service methods

| Method                    | Input                    | Result               |
| ------------------------- | ------------------------ | -------------------- |
| `connection.inspect`      | `InspectInput`           | `ConnectionSnapshot` |
| `connection.connect`      | `ConnectInput`           | `ConnectionResult`   |
| `connection.reuse`        | `ReuseInput`             | `Connected`          |
| `connection.removeDomain` | `RemoveDomainInput`      | `RemoveDomainResult` |
| `provisioning.plan`       | `ProvisioningPlanInput`  | `ProvisioningPlan`   |
| `provisioning.apply`      | `ProvisioningApplyInput` | `ApplyResult`        |
| `verification.observe`    | `ObserveInput`           | `Observation`        |
| `cleanup.plan`            | `CleanupPlanInput`       | `CleanupPlan`        |
| `cleanup.apply`           | `CleanupApplyInput`      | `CleanupResult`      |

The canonical `Interface` returns Effect values with `Failure` in the error channel. `Service` is
the Effect context service accepted by the React root.

## Connection wire models

- `Provider` describes display-safe provider identity and authentication methods.
- `Connected`, `Disconnected`, and `Unsupported` form `ConnectionSnapshot`.
- `ConnectionResult` is either `Connected` or `Redirect`.
- `RemoveDomainInput` requires `preserveDns: true`; DNS deletion is the independent cleanup flow.

## Plan and result wire models

- `ProvisioningPlan` contains `digest`, `expiresAt`, and `PlanOperation` values.
- `PlanOperation` is `Create`, `Noop`, or `Conflict`.
- `ApplyResult` is `Applied`, `Partial`, or `Stale` and contains per-operation results when present.
- `CleanupPlan` contains receipt-bound `Delete`, `AlreadyAbsent`, or `Blocked` operations.
- `CleanupResult` is `Cleaned`, `Partial`, or `Stale`.

The browser submits only the persisted digest when applying a plan. The server retrieves the plan,
checks the authenticated actor, authorizes the requested operation, and stores the returned result.

## Observation wire models

`ObserveInput.sources` explicitly enables provider and public-DNS evidence. `Observation` returns
each source separately as `Found`, `Mismatch`, `Missing`, or `Unavailable` evidence. The host maps
that evidence into product status and retry policy.

## Promise adapter

`AsyncInterface` mirrors all service methods with Promises. Use `fromAsync` to produce an Effect
`Interface`, or `layerFromAsync` to produce a `Layer<Transport.Service>` directly. `toAsync` adapts an
environment-free Effect implementation to Promises. `AsyncOptions.onError` can normalize foreign
failures into `Transport.Failure`.

```ts
import { Transport } from "domainkit";

export const layer = Transport.layerFromAsync({
  connection: api.connections,
  provisioning: api.provisioning,
  verification: api.verification,
  cleanup: api.cleanup,
});
```

See [React transport integration](/docs/react/transport) for a host architecture and security
checklist.