Driftwatch

Resend / Resend API /

Breakingdirection flip: their tools call this safe

content_disposition gained response values

What changed

Producer-side tools call this additive. It breaks exhaustive switches, strict parsers and generated client enums.

Affects attachments[].content_disposition on GetReceivedEmailResponse reachable from 1 operation.

can now return null

Who is affected

Code that reads Resend's GetReceivedEmailResponse objects, used by 2 Resend operations.

Before and after

WhereBeforeAfter
GetReceivedEmailResponse.attachments[].content_disposition"attachment", "inline""attachment", "inline", null
ListAttachmentsResponse.data[].content_disposition"attachment", "inline""attachment", "inline", null
ListReceivedEmailsResponse.data[].attachments[].content_disposition"attachment", "inline""attachment", "inline", null
RetrievedAttachment.content_disposition"attachment", "inline""attachment", "inline", null

Code that breaks

switch (response.attachments[0].content_disposition) {
  // existing branches …

  default:
    throw new Error("unexpected content_disposition");
}

Based on Resend’s published API specification. How severity is decided.