# Migrate from raw HTTP to SDK [#migrate-from-raw-http-to-sdk]

Use this guide when a server-side TypeScript caller currently uses raw HTTP
but can import the SDK directly.

## Before you start [#before-you-start]

* Confirm the caller runs in a TypeScript runtime that can import workspace or
  published packages.
* Keep HTTP when calculation belongs on the server or the caller cannot import
  TypeScript packages. Browser callers can use the SDK's browser-safe exports
  when calculation should run on their device.
* Read [Plain SDK](/sdk/plain-sdk).

## Steps [#steps]

1. Replace the fetch request with an SDK helper.
2. Replace JSON tagged values with constructors such as `aud` and `GrossPay`.
3. Replace HTTP error envelope handling with `TaxKit.safe.calculate` where
   you need result values.
4. Keep integration tests for the same input and expected cents.

## Example [#example]

Before:

```ts
const response = await fetch(
  "http://127.0.0.1:4000/api/v1/calculators/au.income-tax.annual/calculate",
  {
    method: "POST",
    headers: { "content-type": "application/json" },
    body: JSON.stringify({
      facts: {
        taxableIncome: { _tag: "Money", cents: 9000000, currency: "AUD" },
      },
      jurisdiction: "AU",
      taxYear: "2025-26",
    }),
  }
);

const body = await response.json();
```

After:

```ts
import { Cents, aud } from "@taxkit/core/primitives";
import { au } from "@taxkit/sdk/au";

const report = await au.incomeTax.annual({
  taxableIncome: aud(Cents.make(9_000_000)),
});
```

## Verify the result [#verify-the-result]

Both calls should produce annual tax liability of `1958800` cents for taxable
income of $90,000.00 in the retained 2025–26 fixture. See
[the annual calculation guide](/guides/calculate-annual-income-tax) for the
pending Medicare threshold review and the limit on current-law claims.

## Handle errors [#handle-errors]

Raw HTTP returns `CalculatorApiErrorEnvelope`. The SDK safe facade returns
`TaxKitFailure`:

```ts
const result = await au.incomeTax.safe.annual({
  taxableIncome: aud(Cents.make(9_000_000)),
});

if (result._tag === "TaxKitFailure") {
  console.error(result.error.message);
}
```

## Related pages [#related-pages]

* [Choose SDK or HTTP API](/start/choose-sdk-or-api)
* [API overview](/api/overview)
* [Plain SDK](/sdk/plain-sdk)