Introducing attachment uploads in the professional claims form
Nov 19, 2025
Products
You can now upload claim attachments using the professional claims submission form in the Stedi portal.
Previously, you could only upload attachments using Stedi’s Create Claim Attachment JSON API endpoint.
When to include attachments
Some payers require supporting documents, such as X-rays or treatment plans, before approving claims for certain services.
The type of document required varies by payer and service. Without required attachments, the payer may delay (pend) or deny the claim.
How to access the form
Sign in to your Stedi account and go to https://portal.stedi.com/app/healthcare/claims/create.
You can also open the form from the Stedi portal by going to Claims > Submit claim.
How to upload attachments
For claim-level attachments, use Box 19 – Supplemental claim information.

For service-line attachments, use Box 24 – Service lines supplemental information.

You can upload JPG, PDF, PNG, or TIFF files as attachments. To upload an attachment, you must set the Transmission code to EL (EDI).
You must also choose the appropriate Report type for the attachment. For example, if you’re uploading a medical record, you’d select a Report type of M1 – Medical Record Attachment. See Attachment Report Type Codes for a full list.
Note: You can’t add attachments to claims that were already submitted through the portal. To include attachments for those claims, resubmit them with the attachments.
Behind the scenes
When you upload an attachment and submit the claim, Stedi sends the attachment to the payer as a separate X12 275 unsolicited claim attachment transaction behind the scenes. Stedi submits the claim as an 837P professional claims transaction.
Stedi automatically generates an attachment control number and places it in the right fields of the underlying 837P and 275 transactions. The payer uses this number to match the attachment with the claim.
Supported payers
You can only upload attachments if the payer supports 275 claim attachment transactions. You can check payer support using the Stedi Payer Network or Payers API.
Pricing
Attachment uploads are available in the professional claims submission form for all Stedi plans. For per-attachment costs, see our pricing page.
Try it today
To try out the new attachment functionality, sign up for a Stedi account. It takes less than two minutes.
You can now upload claim attachments using the professional claims submission form in the Stedi portal.
Previously, you could only upload attachments using Stedi’s Create Claim Attachment JSON API endpoint.
When to include attachments
Some payers require supporting documents, such as X-rays or treatment plans, before approving claims for certain services.
The type of document required varies by payer and service. Without required attachments, the payer may delay (pend) or deny the claim.
How to access the form
Sign in to your Stedi account and go to https://portal.stedi.com/app/healthcare/claims/create.
You can also open the form from the Stedi portal by going to Claims > Submit claim.
How to upload attachments
For claim-level attachments, use Box 19 – Supplemental claim information.

For service-line attachments, use Box 24 – Service lines supplemental information.

You can upload JPG, PDF, PNG, or TIFF files as attachments. To upload an attachment, you must set the Transmission code to EL (EDI).
You must also choose the appropriate Report type for the attachment. For example, if you’re uploading a medical record, you’d select a Report type of M1 – Medical Record Attachment. See Attachment Report Type Codes for a full list.
Note: You can’t add attachments to claims that were already submitted through the portal. To include attachments for those claims, resubmit them with the attachments.
Behind the scenes
When you upload an attachment and submit the claim, Stedi sends the attachment to the payer as a separate X12 275 unsolicited claim attachment transaction behind the scenes. Stedi submits the claim as an 837P professional claims transaction.
Stedi automatically generates an attachment control number and places it in the right fields of the underlying 837P and 275 transactions. The payer uses this number to match the attachment with the claim.
Supported payers
You can only upload attachments if the payer supports 275 claim attachment transactions. You can check payer support using the Stedi Payer Network or Payers API.
Pricing
Attachment uploads are available in the professional claims submission form for all Stedi plans. For per-attachment costs, see our pricing page.
Try it today
To try out the new attachment functionality, sign up for a Stedi account. It takes less than two minutes.
You can now upload claim attachments using the professional claims submission form in the Stedi portal.
Previously, you could only upload attachments using Stedi’s Create Claim Attachment JSON API endpoint.
When to include attachments
Some payers require supporting documents, such as X-rays or treatment plans, before approving claims for certain services.
The type of document required varies by payer and service. Without required attachments, the payer may delay (pend) or deny the claim.
How to access the form
Sign in to your Stedi account and go to https://portal.stedi.com/app/healthcare/claims/create.
You can also open the form from the Stedi portal by going to Claims > Submit claim.
How to upload attachments
For claim-level attachments, use Box 19 – Supplemental claim information.

For service-line attachments, use Box 24 – Service lines supplemental information.

You can upload JPG, PDF, PNG, or TIFF files as attachments. To upload an attachment, you must set the Transmission code to EL (EDI).
You must also choose the appropriate Report type for the attachment. For example, if you’re uploading a medical record, you’d select a Report type of M1 – Medical Record Attachment. See Attachment Report Type Codes for a full list.
Note: You can’t add attachments to claims that were already submitted through the portal. To include attachments for those claims, resubmit them with the attachments.
Behind the scenes
When you upload an attachment and submit the claim, Stedi sends the attachment to the payer as a separate X12 275 unsolicited claim attachment transaction behind the scenes. Stedi submits the claim as an 837P professional claims transaction.
Stedi automatically generates an attachment control number and places it in the right fields of the underlying 837P and 275 transactions. The payer uses this number to match the attachment with the claim.
Supported payers
You can only upload attachments if the payer supports 275 claim attachment transactions. You can check payer support using the Stedi Payer Network or Payers API.
Pricing
Attachment uploads are available in the professional claims submission form for all Stedi plans. For per-attachment costs, see our pricing page.
Try it today
To try out the new attachment functionality, sign up for a Stedi account. It takes less than two minutes.
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Stedi is a registered trademark of Stedi, Inc. All names, logos, and brands of third parties listed on our site are trademarks of their respective owners (including “X12”, which is a trademark of X12 Incorporated). Stedi, Inc. and its products and services are not endorsed by, sponsored by, or affiliated with these third parties. Our use of these names, logos, and brands is for identification purposes only, and does not imply any such endorsement, sponsorship, or affiliation.
Get updates on what’s new at Stedi
Backed by
Stedi is a registered trademark of Stedi, Inc. All names, logos, and brands of third parties listed on our site are trademarks of their respective owners (including “X12”, which is a trademark of X12 Incorporated). Stedi, Inc. and its products and services are not endorsed by, sponsored by, or affiliated with these third parties. Our use of these names, logos, and brands is for identification purposes only, and does not imply any such endorsement, sponsorship, or affiliation.
Developers
Resources
Get updates on what’s new at Stedi
Backed by
Stedi is a registered trademark of Stedi, Inc. All names, logos, and brands of third parties listed on our site are trademarks of their respective owners (including “X12”, which is a trademark of X12 Incorporated). Stedi, Inc. and its products and services are not endorsed by, sponsored by, or affiliated with these third parties. Our use of these names, logos, and brands is for identification purposes only, and does not imply any such endorsement, sponsorship, or affiliation.