Attachments

Upload and manage files attached to an invoice, an estimate, or a transaction.

Attachments require an active Pro Plan. See Limits for file size, file types, and quotas, or the attachments guide in our help center for a walkthrough.

Upload Attachment

POST https://api.invoiless.com/v1/attachments

Upload a file and attach it to a source document. This endpoint expects multipart/form-data, not JSON.

Example:

curl https://api.invoiless.com/v1/attachments \
  -H "api-key: your-api-key" \
  -F "file=@contract.pdf" \
  -F "source=source-id" \
  -F "sourceType=Invoice"

Form Parameters

Name	Type	Description	Required
file	file	The file to upload (max 2 MB). See Allowed file types	Yes
source	string	Id of the document to attach the file to (invoice, estimate, or transaction id)	Yes
sourceType	string	Source type, possible values are Invoice, Estimate, or Transaction	Yes

The attachment name is taken from the uploaded file name (without its extension) and sanitized. Use Update Attachment to rename it.

Get Attachments

GET https://api.invoiless.com/v1/attachments/source/:id

Retrieve all attachments of a source document.

Path Parameters

Name	Type	Description	Required
id	string	Invoice, estimate, or transaction id	Yes

Each attachment carries a url, a signed download link that expires one hour after it is issued. Request the list again to get a fresh link — don't store it.

Update Attachment

PATCH https://api.invoiless.com/v1/attachments/:id

Rename an attachment. The file itself cannot be replaced — upload a new attachment and delete the old one instead.

Example:

{
  "name": "Signed contract"
}

Path Parameters

Name	Type	Description	Required
id	string	Attachment id	Yes

Body Parameters

Name	Type	Description	Required
name	string	Attachment name (max 50 characters)	Yes

Delete Attachment

DELETE https://api.invoiless.com/v1/attachments/:id

Delete an attachment. The file stays recoverable for 30 days before it is permanently removed from storage.

Path Parameters

Name	Type	Description	Required
id	string	Attachment id	Yes

Limits

Limit	Value
File size	2 MB per file
Attachments per source	3
Attachments per account	10 free, plus purchased credits

The Pro Plan comes with 10 free attachments. Need more? Buy additional credits from Settings > Billing — each credit raises the per-account limit.

Deleting an attachment frees a slot against the per-source limit right away. Against the per-account limit it only frees a slot if it is deleted within 24 hours of being uploaded.

Allowed file types

Category	Types
Images	.jpg, .jpeg, .png
Documents	.pdf, .doc, .docx, .xls, .xlsx
Text & data	.txt, .csv
Compressed	.zip

Uploading any other type returns 403 Forbidden with the message Mime type is not allowed.

Error codes

Status	Code	Meaning
403	ATTACHMENTS_PRO_ONLY	Attachments require an active Pro Plan
403	ATTACHMENT_LIMIT_REACHED	The account attachment quota is reached — details.maxAttachments is its value