Get subscription by ID

{  "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": [],  "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": "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"  }}