PayPerFax

Prepare a fax for a person to send with PayPerFax, the pay-per-fax service: no account, no subscription, one payment for one fax. A common use is a letter or a form for the IRS, a doctor, a court, an insurer or a landlord. The tool does not send the fax and does not charge. It returns a link for the person. The person opens the link, sees the preview and the price, and pays in the browser. Then the fax is sent. Rules: 1. Email: ask the person for their email address. Do not guess it. The confirmation and the receipt go there. 2. A document that the person has as a file (a PDF, a scan, a signed form): do not retype it as text. A typed copy of a signed form is not the form. Set file_expected to true, and tell the person that they add the file on the page of the link. 3. The fax number of an agency or a company: take it from its official website (for the IRS: irs.gov), and show the person the source. A number from memory can send private papers to a stranger. 4. A letter that you write goes in markdown. With no cover page, the letter must have its own date, names and address block. With a cover page, keep cover_message short: a long message is cut off. 5. Limits: the markdown text can be at most 100 KB. Headings, lists, bold text and tables are printed. An image is printed as its alt text, a link as its text, and raw HTML as text. 6. If you can run shell commands and the document is a local file, send it with the HTTP call: curl -F "to=+14155550101" -F "email=person@example.com" -F "documents[]=@/path/to/file.pdf" https://fax.payperfax.com/api/fax 7. After the call, give the person the link, and say that nothing is sent and nothing is charged before they pay. The confirmation email comes after the payment. If the status of the fax is later "failed", the person is not charged, and can send the fax again.

Read where a fax is. Give the id from create_fax, or an address of the fax: the status address from the tracking prompt of the person, or the address of a page of the fax. "status" is pending, delivered, failed or expired. While it is pending, "stage" says more: rendering (we prepare the pages), awaiting_payment (the person did not pay yet; "pages" and "price" are given, and they can still change), sending (paid, on its way). delivered: the fax arrived. failed: the fax was not delivered, the person is not charged, and can send it again; with "render_failed", the document could not be prepared, and the person opens the link to change it. expired: the fax was not paid in time, or it is no longer available. Do not call this in a loop: read the status when the person asks.

List what PayPerFax can fax, and the limits: the text that create_fax takes, the file types that a person can add on the form or that a shell can send to the HTTP call, the sizes, and the languages.