Send a Fax

Submit a fax for delivery. The file is staged and the fax is queued for processing. A credit hold is placed on submission and captured on delivery or released on failure.

POST /faxes

Send a Fax

cURL

curl --request POST \
  --url https://api.mintfax.com/v1/faxes \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'to=<string>' \
  --form file='@example-file' \
  --form 'webhook_url=<string>' \
  --form max_attempts=3 \
  --form 'csid=<string>' \
  --form 'tags=<string>'

201

Example

{
  "id": "<string>",
  "to": "<string>",
  "tags": {},
  "created_at": "2023-11-07T05:31:56Z",
  "resent_from": "<string>"
}

Authorizations

Authorization · string · header · required

API key as Bearer token. Use an account key (mfx_acct_...) for /account/* endpoints, and an environment key (mfx_test_... for sandbox, mfx_live_... for live) for /environment/*, /faxes, /webhooks, and /events.

Headers

Idempotency-Key · string

Client-generated key for idempotent submission (recommended). Duplicate keys return the original response without re-processing. Keys expire after 24 hours.

Body

multipart/form-data

to · string · required

Pattern: ^\+[1-9]\d{1,14}$

file · file · required

Maximum string length: 10240

webhook_url · string<uri> | null

Maximum string length: 2048

max_attempts · integer | null

Required range: 1 <= x <= 5

csid · string | null

Maximum string length: 20

page_size · enum<string> | null

Available options: letter, legal, a4, b4

resolution · enum<string> | null

Available options: standard, fine

optimize_for · enum<string> | null

Available options: text, photo

tags · string[] | null

Maximum array length: 10

Maximum string length: 255

Response

201

application/json

FaxSubmissionResource

id · string · required

Unique fax identifier (fax_-prefixed).

Example:

"fax_8aZqRm4yT3vK7pNxJ2bH9c"

status · enum<string> · required

Initial fax status.

Available options: queued, submitted, in_progress, delivered, failed

Example:

"queued"

to · string | null · required

Destination fax number in E.164 format.

Example:

"[phone]"

tags · object · required

Echo of caller-supplied metadata. Empty serializes as {}.

Show child attributes

created_at · string<date-time> · required

UTC timestamp when the fax record was created.

resent_from · string

Original fax identifier when this submission is a resend; only present on resends.

Example:

"fax_8aZqRm4yT3vK7pNxJ2bH9c"