SingleFax API
SingleFax API: A flexible fax API with strong developer tooling, but only 10 pages in its $9.99 monthly entry plan. Ranked #13 of 26 in Fax APIs by our editors (6.4/10); pricing: From $9.99/mo; best for developers wanting flexible prepaid fax options.
At a glance
- Editor score6.4 / 10
- PricingFrom $9.99/mo
- Best forDevelopers wanting flexible prepaid fax options
- Free planNo
- Paid from$9.99/mo
- Inbound faxingYes
- Facts checked20 Sep 2026
Where it wins
- Signed webhooks and delivery-attempt retrieval support status workflows.
- Scoped API keys and prepaid credits support controlled integrations.
- Node.js, Python, Go, PHP, cURL, CLI, and multiple upload formats are supported.
Where it doesn't
- The $9.99 monthly entry plan includes only 10 pages.
- The public API does not support PHI.
- Higher-volume plans are presented mainly as company or annual options.
Our verdict on SingleFax API
SingleFax API is a hosted REST interface for sending and receiving faxes from server-side applications. It is aimed at developers who need outbound faxing, inbound fax records, dedicated US or Canadian numbers, and programmatic delivery tracking. Documents can be submitted as base64, multipart uploads, or upload tokens, while scoped API keys, prepaid credits, and a checkout API support application-controlled billing. The API is intended for backend integrations and does not support PHI.
Pricing covers several usage patterns. A one-time fax costs $0.99 for up to 10 pages, with payment only on successful delivery and a timestamped transmission receipt. Receiving faxes for 30 days costs $4.99 and includes a dedicated US or Canadian number, the first inbound fax, and PDF delivery to email. Lifetime Basic costs $97 with a permanent fax line, starter credit, and 1 GB of storage; Lifetime Pro costs $147 and adds a vanity or toll-free number and 5 GB of storage. Company Plans start at $9.99 per month, while Standard costs $99 per year for 300 pooled pages per month and Business costs $299 per year for 1,000 pooled pages per month.
The strongest fit is an engineering team that values implementation flexibility: signed events cover queued, delivered, and failed faxes, and examples are available for Node.js, Python, Go, PHP, and cURL. Inbound numbers and status retrieval also support workflows that need more than one-way sending. The tradeoff is scale at the entry point: the $9.99 monthly plan includes only 10 pages, so higher-volume users should evaluate the annual company plans. Organizations handling PHI should choose an alternative, while developers building general fax workflows can benefit from SingleFax's API, web, and prepaid options.
SingleFax API pricing
All 7 SingleFax API plans and prices →
SingleFax API fact sheet
| Free plan | No |
|---|---|
| Paid from | $9.99/mo |
| Inbound faxing | Yes |
| Outbound faxing | Yes |
| Delivery tracking | Yes |
| Webhook events | Yes |
| API protocol | Rest |
| Included pages | 10 pages |
| Money-back guarantee | 30 days |
| Deployment | Cloud |
| Platforms | Web |
| Support | Email, Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | From $9.99/mo (source) |
| Website | singlefax.com |
| Facts checked | 20 Sep 2026 |
Alternatives to SingleFax API
- Telnyx Fax APIA low per-page REST fax API with inbound, outbound, tracking, and webhook support.9.5
- PhaxioA feature-rich fax API for sending, receiving, tracking, and routing documents.8.8
- FaxxingA practical free-start fax API with inbound support, signed webhooks, and usage-based pricing.8.3
See all SingleFax API alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Sep 2026
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