curl --request PUT \
  --url https://commet.co/api/v1/subscriptions/{id}/offer \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "offerId": "<string>"
}
'

import { Commet } from "@commet/node";

const commet = new Commet({ apiKey: "ck_xxx" });

const subscription = await commet.subscriptions.applyOffer({
  id: "sub_xxx",
  offerId: "ofr_xxx",
});

from commet import Commet

commet = Commet("ck_xxx")

subscription = commet.subscriptions.apply_offer(
    "sub_xxx",
    offer_id="ofr_xxx",
)

client, err := commet.New("ck_xxx")
if err != nil {
	log.Fatal(err)
}
ctx := context.Background()

subscription, err := client.Subscriptions.ApplyOffer(ctx, "sub_xxx", &commet.ApplySubscriptionOfferParams{
	OfferID: "ofr_xxx",
})
if err != nil {
	log.Fatal(err)
}

import co.commet.Commet;
import co.commet.params.ApplySubscriptionOfferParams;

var commet = Commet.builder().apiKey("ck_xxx").build();

var subscription = commet.subscriptions().applyOffer(
    "sub_xxx",
    ApplySubscriptionOfferParams.builder("ofr_xxx").build()
);

use Commet\Commet;

$commet = new Commet('ck_xxx');

$subscription = $commet->subscriptions->applyOffer(
    id: 'sub_xxx',
    offerId: 'ofr_xxx',
);

{
  "id": "sub_1a2b3c4d",
  "customerId": "cus_1a2b3c4d",
  "plan": {
    "id": "plan_1a2b3c4d",
    "name": "Pro",
    "basePrice": 2000
  },
  "name": "Pro",
  "description": null,
  "status": "active",
  "billingInterval": "monthly",
  "trialEndsAt": null,
  "currentPeriod": {
    "start": "2026-09-07T12:00:00.000Z",
    "end": "2026-10-07T12:00:00.000Z",
    "daysRemaining": 30
  },
  "cancellation": null,
  "cancelAtPeriodEnd": false,
  "scheduledPlanChange": null,
  "startDate": "2026-09-07T12:00:00.000Z",
  "endDate": null,
  "billingDayOfMonth": 7,
  "nextBillingDate": "2026-10-07T12:00:00.000Z",
  "checkoutUrl": null,
  "createdAt": "2026-09-07T12:00:00.000Z",
  "updatedAt": "2026-09-07T12:00:00.000Z",
  "offerApplications": [
    {
      "id": "application_1a2b3c4d",
      "name": "Launch discount",
      "appliesTo": {
        "type": "plan_price",
        "id": "price_1a2b3c4d"
      },
      "offerId": "offer_1a2b3c4d",
      "source": "direct",
      "status": "applied",
      "currency": "usd",
      "subtotal": 2000,
      "discountAmount": 400,
      "total": 1600,
      "phases": [
        {
          "type": "percentage",
          "durationCycles": 3,
          "durationInterval": "monthly",
          "percentage": 20,
          "startsAt": "2026-09-07T12:00:00.000Z",
          "endsAt": "2026-12-07T12:00:00.000Z"
        }
      ],
      "quotedAt": "2026-09-07T12:00:00.000Z",
      "expiresAt": null,
      "appliedAt": "2026-09-07T12:00:00.000Z"
    }
  ],
  "pause": null,
  "priceId": "price_1a2b3c4d",
  "object": "subscription",
  "livemode": false,
  "consumptionModel": "metered",
  "features": [
    {
      "code": "api_calls",
      "name": "API Calls",
      "type": "usage",
      "usage": {
        "current": 250,
        "included": 1000,
        "overageQuantity": 0,
        "unlimited": false
      }
    }
  ],
  "credits": null,
  "balance": null
}

{
  "error": {
    "type": "validation_error",
    "code": "validation_error",
    "message": "The request contains an invalid parameter.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/validation_error.md"
  }
}

{
  "error": {
    "type": "authentication_error",
    "code": "unauthorized",
    "message": "A valid API key is required.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/unauthorized.md"
  }
}

{
  "error": {
    "type": "authentication_error",
    "code": "forbidden",
    "message": "You do not have permission to perform this operation.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/forbidden.md"
  }
}

{
  "error": {
    "type": "not_found_error",
    "code": "not_found",
    "message": "The requested resource was not found.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/not_found.md"
  }
}

{
  "error": {
    "type": "conflict_error",
    "code": "idempotency_in_progress",
    "message": "A request with this idempotency key is still being processed.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/idempotency_in_progress.md"
  }
}

{
  "error": {
    "type": "rate_limit_error",
    "code": "rate_limited",
    "message": "Too many requests. Retry after the interval specified in the Retry-After header.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/rate_limited.md"
  }
}

{
  "error": {
    "type": "internal_error",
    "code": "internal_error",
    "message": "An unexpected error occurred while processing the request.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/internal_error.md"
  }
}

{
  "error": {
    "type": "internal_error",
    "code": "idempotency_unavailable",
    "message": "Idempotency storage is temporarily unavailable. Retry with the same idempotency key.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/idempotency_unavailable.md"
  }
}