Idempotency Headers

For any idempotent endpoints, Fern’s SDKs will allow you to specify idempotency headers. Typically the headers include Idempotency-Key, but you can also specify additional headers.

1
const response = await client.transactions.send({
2
  amount: 100,
3
  currency: "usd",
4
}, {
5
  idempotencyKey: "64099353-b48b-4dcd-98b7-74df1cc57933"
6
});

Note that the generated SDKs will not allow you to specify idempotency headers for non-idempotent endpoints. This is to ensure that the user knows exactly which invocations are idempotent and which are not.

Configuration

To enable idempotency headers in your API, you need to do the following in your overrides file:

1. Configure the idempotency headers
2. Mark individual endpoints as idempotent

1
# Configure the idempotency headers
2
x-fern-idempotency-headers:
3
  - header: IDEMPOTENCY-KEY
4
    name: idempotency_key
5
6
# Mark an individual endpoint as idempotent
7
paths:
8
  /foo:
9
    post:
10
      x-fern-idempotent: true