SingleFax

SingleFax Send a fax from Claude, ChatGPT, Cursor, or any MCP client.

CommunityOnlineNo sign-inGlobalFreeCan modify data

What it can do

  • List Skus: Catalog of SingleFax SKUs with prices. Send a document with create_fax_draft. Get a number with create_inbound_number. Credits with create_checkout. PDF, Word, Excel, PowerPoint, RTF, plain
  • Quote Fax: Retail send quote without charging. Pass to (E.164). Optional pages (default 10) or base64 of the document for a live page count. Optional contentType when MIME is missing.
  • Get Credits: Read prepaid credit balance

What data it sees

Do you need an account

No: the server works without sign-in

SingleFax

Send a fax from Claude, ChatGPT, Cursor, or any MCP client. Upload a PDF, quote pages, pay, and poll delivery status. MCP: https://singlefax.com/mcp (Streamable HTTP + OAuth)
Docs: singlefax.com/agents HIPAA / PHI is not available on MCP. Use the website HIPAA Secure path with an electronic BAA.

Connect

Sign in with OAuth when the client prompts. No API key.

claude mcp add --transport http singlefax https://singlefax.com/mcp
Server tool list (10)

Raw names from tools/list. Only developers need these.

list_skusCatalog of SingleFax SKUs with prices. Send a document with create_fax_draft. Get a number with create_inbound_number. Credits with create_checkout. PDF, Word, Excel, PowerPoint, RTF, plain text, and images (JPEG, PNG, TIFF, GIF, WebP, BMP, HEIC). Do not convert to PDF first — send the original file. We convert to PDF before sending. HIPAA, EIN, and IRS forms are website-only (URLs included).
quote_faxRetail send quote without charging. Pass to (E.164). Optional pages (default 10) or base64 of the document for a live page count. Optional contentType when MIME is missing.
get_creditsRead prepaid credit balance
get_fax_statusGet fulfillment/payment status for a fax order you own
list_numbersList this account's active inbound fax numbers (E.164, type, expiry). After create_inbound_number checkout completes, call this to read the number.
create_uploadOptional. For files too large for a tool-call. Returns uploadPageUrl (human drop, no login) and uploadUrl (HTTP PUT raw bytes, no Authorization). Pass uploadToken to poll stored, then create_fax_draft.
create_fax_draftSend a fax from this authenticated session. Pass to plus uploadToken from create_upload after the file is stored. base64 only for tiny files (under ~20KB). Optional contentType when sniffing is needed. For larger files: create_upload → user opens uploadPageUrl → create_fax_draft({ to, uploadToken }). Queues on credits or a page pool; otherwise returns checkoutUrl. PDF, Word, Excel, PowerPoint, RTF, plain text, and images (JPEG, PNG, TIFF, GIF, WebP, BMP, HEIC). Do not convert to PDF first — send the original file. We convert to PDF before sending.
create_machine_faxAutonomous MPP path — returns payment_required challenge when unpaid, then charges on retry with payment_authorization
create_inbound_numberReserve a dedicated inbound fax number and return Stripe Checkout. Default sku inbound_30day ($4.99). Also lifetime-basic, lifetime-pro, monthly-basic, annual-basic, monthly-business, annual-business. Optional country US|CA and state. Returns checkoutUrl plus the reserved phoneNumber. After the user pays, call list_numbers. Free 24-hour numbers, vanity digits, HIPAA, EIN, and IRS stay on the website.
create_checkoutStart Stripe Checkout for a catalog SKU. Prefer create_inbound_number for a fax number. sku: credit_pack | inbound_30day | monthly-basic | annual-basic | monthly-business | annual-business | lifetime-basic | lifetime-pro. HIPAA/EIN/IRS are website-only (list_skus). Do not use this to send a document — use create_fax_draft.