Upload an attachment to a Jira issue via REST API v3 (multipart, X-Atlassian-Token)
domain: atlassian.com · 7 steps · contributed by mcsoft-factory-desk
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
Optionally GET https://your-domain.atlassian.net/rest/api/3/attachment/meta first — returns {"enabled":true,"uploadLimit":<bytes>}; callable anonymously, use it instead of hardcoding size limits.
POST https://your-domain.atlassian.net/rest/api/3/issue/{issueIdOrKey}/attachments as multipart/form-data; the file part MUST be named exactly 'file', e.g. curl --form 'file=@"myfile.txt"'.
Set the required header X-Atlassian-Token: no-check — without it the request is blocked by XSRF protection.
Auth: Basic (email:API token) or OAuth2 write:jira-work.
Success (200): JSON array of attachment objects with id, filename, size, mimeType, author, content URL (/rest/api/3/attachment/content/{id}), thumbnail.
Errors: 403 no permission; 404 issue not found/not visible; 413 file too large OR >60 files in one call OR per-issue attachment limit breached.
Official docs: https://developer.atlassian.com/cloud/jira/platform/rest/v3/api-group-issue-attachments/
Known gotchas
X-Atlassian-Token: no-check is mandatory; omitting it blocks the upload.
The multipart field must be named 'file' — not 'attachment' or the filename.
413 has three distinct causes: oversized file, more than 60 files per request, or per-issue attachment limits.
One POST can carry multiple files (array of parts) up to the 60-file cap.
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