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Error codes

unsupported_media_type

Unsupported media type. The API accepts JSON bodies only. A body with any other Content-Type is refused before it is read.

What it means

The API returns HTTP 415 with error.code set to unsupported_media_type. The default message is: "Request bodies must be sent as application/json."

Common causes

• Content-Type missing or set to application/x-www-form-urlencoded, multipart/form-data or text/plain.

How to identify it

Check the response status (415) and error.code (unsupported_media_type). Branch on error.code, not on the message text: messages can be reworded, codes do not change within v1. Log error.request_id (also sent as the X-Request-Id header) so support can find the request.

How to fix it

• Send Content-Type: application/json with a JSON body.

Retry guidance

Sending the request unchanged fails the same way. Fix the cause first (see How to fix it), then send it again.

Did anything happen?

This request was refused before any call was placed and before anything was charged.

Idempotency

Nothing was done. Fix the request and send it again; if you sent an Idempotency-Key you may reuse it, because a refused request is not stored.

Who can fix it

The developer who sends the request can fix it; no administrator action is normally needed.

When to contact support

If the error persists after the steps above, contact support@relationsai.com. See Support for what to include (the request_id, the time in UTC, the operation, and whether you used a test or live key) and what never to send (API keys, Authorization headers, webhook signing secrets, recording links, transcripts or customer data).

Example error response

JSON
{
  "error": {
    "code": "unsupported_media_type",
    "message": "Request bodies must be sent as application/json.",
    "details": {},
    "request_id": "req_ddqcfray35osp7oqwlonif36",
    "retry": "no",
    "doc_url": "https://docs.relationsai.com/errors/unsupported_media_type"
  }
}

Incorrect and corrected request

Incorrect: A form-encoded body; the API reads JSON only.

Text
POST /v1/contacts
Authorization: Bearer rai_test_YOUR_TEST_KEY
Content-Type: application/x-www-form-urlencoded

phone_number=%2B12025550100&name=Asha

Corrected: The same contact as a JSON body with Content-Type application/json.

Text
POST /v1/contacts
Authorization: Bearer rai_test_YOUR_TEST_KEY
Content-Type: application/json

{
  "phone_number": "+12025550100",
  "name": "Asha"
}

Operations that can return this error

• POST /calls: Place a call
• POST /campaigns: Create a campaign
• PATCH /campaigns/{campaign_id}: Update a campaign
• POST /campaigns/{campaign_id}/recipients: Add recipients
• POST /contacts: Create a contact
• POST /contacts/upsert: Create or update a contact by phone number
• PATCH /contacts/{contact_id}: Update a contact
• POST /dnc-entries: Add a number to the do-not-call list
• POST /webhook-endpoints: Create a webhook endpoint
• PATCH /webhook-endpoints/{webhook_endpoint_id}: Update a webhook endpoint
• POST /webhook-endpoints/{webhook_endpoint_id}/rotate-secret: Rotate a webhook signing secret

See all codes in the error-code reference.