Trello card attachments
- Free allowance
- 10 MB per attachment on Free, 250 MB on Standard — and explicitly 'there is no total limit for storage, just a per-file limit'
- Verdict
- caveatusable, with a named limit or an unprobed read path
- Cost
- free tier
- Identity
- institution?placeholder, not evidence; card unknown, phone unknown
- Binding limit
- per-object-cap10 MB/file
- Evidence
- reported3 sources; a third party said so
- Freshness
- stale on 2026-11-05checked 2026-10-21 (inherited); stale on 2026-11-05
| Free tier | 10 MB per attachment on Free, 250 MB on Standard — and explicitly 'there is no total limit for storage, just a per-file limit' unit unlimited; metered on stored-bytes |
|---|---|
| Price | none stated |
| Limits |
10 MB/file on Free; per-board attachment ceiling exists in the API response model (limits.attachments.perBoard warnAt 32400 / disableAt 36000) — i.e. ~32k attachments/board before hard stop; 10 MB is small for bulk data |
| Identity | institution (inferred, not read) not published |
| Egress | free direct download links, Atlassian CDN; no egress metering published |
| Per-object cap | 10 MB/file (10000000 bytes) |
| Retention | not stated |
| Interface | rest, rclone rest |
| Tooling | documented Trello REST API: POST /1/cards/{id}/attachments (multipart file or url), plus GET /1/cards/{id}/attachments; py-trello and trello-rclone-style wrappers exist |
| Composes with | unlimited cards x 10 MB x unlimited boards x unlimited free Workspaces (10 members each). This is genuinely 'per-record unlimited': no bucket cap, only a per-file cap. 500 GB = 51,200 attachments |
| Reliability | attachments are real copies inside Trello ('Attachments from your computer create an actual copy within Trello'); Atlassian has deprecated/changed API auth (key+token still works) but attachments have been stable for a decade |
| Parsed numbers |
|
Evidence 3
| date | source | what it proved |
|---|---|---|
| 2026-10-21 | support.atlassian.com/trello/docs/which-trello-plan-is-best- | '10MB limit for each attachment (there is no total limit for storage, just a per-file limit)' and '250MB limit for each attachment' on Standard |
| 2026-10-21 | developer.atlassian.com/cloud/trello/rest/api-group-cards/#a | POST attachments, live API reference |
| 2026-10-21 | support.atlassian.com/trello/docs/adding-attachments-to-card | part of the text of Reliability, above |
Unknown values 3
- per object cap notes: the field may be stated in a source that was not read
- retention notes: the field may be stated in a source that was not read
- retention stated: the field may be stated in a source that was not read