# SingleFax

SingleFax is a pay-per-fax service operated by Monocube LLC. Send or receive a fax from the web, email, REST API, or an AI agent. No subscription required for a one-time send.

## When to use this

Use SingleFax when the user asked you to **send a fax**, **deliver a document to a fax number**, or **pay per fax** without a monthly plan. Destinations we support; domestic base is $0.99 for up to 10 billable pages, then about +$0.08/page (cap 100). PDF, Word, Excel, PowerPoint, RTF, plain text, and images are accepted. Do not convert to PDF first. Send the original file.

Do **not** use MCP, MPP, or the public API for PHI. Covered Entities use HIPAA Secure Mode on the website with an electronic BAA.

Paid fax numbers include a searchable transcript and key fields in the dashboard. HIPAA inbound transcripts stay on the website. Agents with `inbox:read` can list received faxes (`list_inbound_faxes` / `GET /api/v1/received-faxes`).

## How agents should call us

| Job | Path |
| --- | --- |
| Chat (Cursor, Claude, ChatGPT, Codex) | MCP OAuth at https://singlefax.com/mcp, `create_upload` then `create_fax_draft({ to, uploadToken })` |
| Backend / scripts | API key `sf_live_…` + prepaid credits, `POST /api/v1/faxes` |
| Autonomous pay | MPP HTTP 402, `POST /api/v1/machine/faxes` (Stripe SPT / Link CLI, or Tempo USDC) |

## Key URLs

- Human install: https://singlefax.com/agents
- REST / CLI docs: https://singlefax.com/developers
- Agent guide: https://singlefax.com/agents.md
- Developer examples: https://singlefax.com/developers.md
- OpenAPI: https://singlefax.com/openapi.json
- Auth: https://singlefax.com/auth.md
- Pricing: https://singlefax.com/pricing.md
- API versioning: https://singlefax.com/versioning.md
- MCP: https://singlefax.com/mcp
- llms.txt: https://singlefax.com/llms.txt
- Privacy: https://singlefax.com/privacy-policy.md
- Refunds: https://singlefax.com/refund-policy.md
- About: https://singlefax.com/about.md
- Contact: https://singlefax.com/contact.md, info@singlefax.com


## Subscription number porting

Free port-in. Port-out costs $10 per number, or $150 for vanity numbers, paid upfront and refunded if the transfer fails.

Eligible US/Canada local port-ins: Standard or Business, monthly or annual, including HIPAA Secure; one number per request. No toll-free, mobile, international, lifetime or 30-day port-ins. New subscription billing starts after carrier completion and verified fax routing, with no temporary number. Existing subscribers preserve billing and page usage and receive 14 days of inbound overlap on their former SingleFax number.

Vanity means North American area code 800 or four identical trailing digits. No free port-out under any plan or after cancellation. Every fee is captured separately from subscription billing. Confirmed terminal failure or cancellation receives the entire fee back, including markup; delays and correctable exceptions do not trigger refunds. Successful port-out stops service and renewal without proration. Ported-in numbers never enter reusable inventory. Pending transfers block release.

Port-out after subscription cancellation is available while the number remains assigned; ordinary cancellation retains pay-as-you-go inbound and the 90-day inactivity policy with notices before release. Start a transfer and review eligibility, documents and progress at https://singlefax.com/number-porting.