Skip to main content
Two endpoints: what is attached, and the file itself. Both take the same mailbox (required) and folder parameters as the message endpoints. Required permission for both: Attachments → Read (attachments:read)
Inline parts are not attachments. A signature logo, a tracking pixel, anything the HTML references with cid: — those are part of the rendered body and are left out of these endpoints.Listing them would turn every marketing email into a pile of phantom downloads, and an integration saving “all attachments” would fill a disk with spacer GIFs.

​
List attachments

Metadata only — deciding whether to fetch a 12 MB PDF should not require fetching it. The same array appears on GET /v1/messages/{uid}, so if you are already reading the message you do not need this call. index is this list’s own ordering, stable for as long as the message is: MIME parts do not reorder themselves. It is what the download endpoint takes.

​
Download an attachment

Returns the raw bytes, not JSON.

​
The content type is ours, not the sender’s

Every byte here describes something a stranger emailed you. A part declaring itself text/html or image/svg+xml and served back verbatim is a script that runs wherever it is opened. So the declared type is only honoured when it is plainly inert — images, audio, video, text/plain, application/pdf. Everything else is served as application/octet-stream, with nosniff so a browser cannot guess its way around the decision. The file itself is unchanged; only the label is. If you need the sender’s declared type, read content_type from the listing above — that one is reported as-is.

​
X-Ruber-File-Risk

Present when the filename’s extension is one that executes: .exe, .js, .lnk, .iso and similar get executable; macro-bearing Office formats get macro. It is a header rather than a refusal. Ruber’s mail plane already scans inbound mail with ClamAV and rejects what it recognises, so this is a second layer for what a scanner cannot catch. The web app uses the same judgement to warn a person before they download; warning a program in prose achieves nothing, and refusing the download would break the legitimate case of an integration archiving everything that arrives. So the judgement travels as a header your code can act on, and the file still comes. Do not execute what arrives here, and be careful about writing it to a path derived from filename — the name comes from the sender and may contain separators or traversal sequences.

​
Errors

Errors are JSON even though a successful response is not. See Errors for the full response shape.