# Submit Claim Attachment Raw X12
Source: https://www.stedi.com/docs/healthcare/api-reference/post-healthcare-submit-claim-attachment-raw-x12

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openapi: claims post /claim-attachments/raw-x12-submission
title: Submit Claim Attachment Raw X12
--------------------------------------

<Warning>
  This endpoint is in **beta** and is subject to change.
</Warning>

This endpoint is ideal if you have an existing system that generates X12 EDI files and you want to send them through Stedi's API.

1. Call this endpoint with a payload in [275 X12 EDI format](https://portal.stedi.com/app/guides/view/hipaa/patient-information-x210/01HQ4HZ8ZBY2CZGPCVVM8JTK22).
2. Stedi sends the attachment to the payer, so the payer can use it to adjudicate the referenced 837 professional, dental, or institutional claim.
3. The endpoint returns summary information about the attachment submission.

This endpoint only supports [unsolicited attachments](/healthcare/submit-claim-attachments#solicited-vs-unsolicited-attachments).

<Note>
  Visit [Claim attachments](/healthcare/submit-claim-attachments#x12-edi-apis) for a
  full how-to guide.
</Note>

## Size limit

The size limit for attachments submitted in a single request is 6MB. If you need to submit larger attachments, you must submit them through [Stedi SFTP](/healthcare/submit-claims-sftp-connection) or the [JSON endpoints](/healthcare/api-reference/post-healthcare-create-claim-attachment).