faxSendSubmit API Paramaters

faxSendSubmit API Paramaters

API Values for faxSendSubmit

Parameters Max Length Description Example
AccountID Int(9) Your Openfax Account ID. 1008001
APIKey VarChar(255) Generated API Key available in your portal. IEYRtw2cd8aGa54
FaxNumber BigInt(20) 11 Digit North American Fax Number. 15555551212
toHeader VarChar(25) Appears in the To: <Value> of fax header. My Customer Name
frHeader VarChar(25) Appear in the Fr: <Value> of fax header.

Note: It is a legal requirement that you accurately represent yourself or your company as the sender of this fax.
My Company Name
paperSize Int(1) Specifies input PDF paper size for TIFF conversion:


0 – US Letter (8.5 x 11.0 in / 216 x 279 mm)
1 – US Legal (8.5 x 14.0 in /216 x 356 mm )

2 – A4 (8.5 x 11.0 in / 216 x 279 mm)

faxResolution Int(1) Fax resolution used for transmission:

0 – Standard Resolution (204 x 98 dpi)
1 – Fine Resolution (204 x 196 dpi)


Note: Fine mode may increase the documents transmission time. Depending on your pricing arrangement transmission times may impact the cost of the fax transmission.

Priority VarChar(6) Transactional faxing will always receive a higher priority on the Openfax network over other fax broadcast traffic.  This affects how quickly your fax will be attempted in relation to other fax traffic on the network.

It is recommended to always use “Normal”, though if your fax is less urgent you may Specify “Low” to give Normal transactional faxes preference over those specific with a Low priority.  It is not possible to change a transactional fax priority once it has been submitted.
Values are case sensitive.
Normal – High transactional priorityLow – Lower transactional priority, other transactions will receive preference within the queue.
PDF_encode Base64 encoded The PDF file is limited to 50MB max and should be base 64 encoded. Limited to 50MB

faxSendSubmit API Responses

Response Returns Condition
Success {

“Response”: “Success”,

“OutTransID”: [id]

Returns the OutTransID for the submitted outbound fax transaction.
Failed {

“Response”: “Failed”,

The total number attempted outbound FaxNumber transactions for the date range provided.
InvalidAuthentication {


The account number or API key provided is invalid.
AccountInactive {


The account has reached the credit limit or has been deactivated, contact customer support.
RestrictedFaxNumber }


The attempted number is restricted from dialing either due to the phone number owner’s request, compliance list or another reason.  Contact customer support for details if required.
InvalidFaxNumberLength {


The FaxNumber is not valid for dialing.  For North American dialing 1NPANXXXXX is required.  International dialing is not supported at this time.
InvalidFaxResolution {


Specified faxResolution value is invalid. Value must be 0 for standard or 1 for fine resultion.
InvalidPapersize {


Specified paperSize value is invalid.  Value must be 0 – US Letter, 1 – US Legal  or 2 – A4.
InvalidPriority {


Specified Priority value is invalid.  Values are case sensitive and should be Normal or Low.

Sending (Outbound) Fax Limitations

Limitations of The Send Fax (Outbound) API Call

  • Limited to 1 PDF file per request
    (The document must be in portrait orientation)
  • US Letter, US Legal & A4 Paper Size
  • Limited to 1 fax destination per API submission
  • All requests must be via HTTPS



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Authentication & Settings

Using the Openfax Cloud Fax API requires an Openfax Account ID and API Key.

  • Your Openfax Account ID is seven digits and is assigned at activation of your development account.
  • Once you have activated your account login to https://portal.openfax.com with your assigned account id and password.
  • Your default API key can be found or changed in the Settings section of your account menu.

Other Account Default Settings

  • Outbound Fax Status Web Service Post Back
  • Inbound Fax Amazon (AWS) S3 Bucket Post
  • Inbound Fax Email Delivery and Notification
  • Inbound Fax Web Service Post Back



Ask us about our Free Cloud Fax API.

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