Sinch Fax API
Sinch Fax API: A mature REST fax API for adding inbound and outbound faxing to business applications. Ranked #4 of 26 in Fax APIs by our editors (9.0/10); pricing: Paid; best for businesses wanting a mature programmable fax service.
At a glance
- Editor score9.0 / 10
- PricingPaid
- Best forBusinesses wanting a mature programmable fax service
- Free planNo
- Inbound faxingYes
- Founded2008 · Stockholm, Sweden
- Facts checked20 Sep 2026
Where it wins
- Supports both outbound transmission and inbound fax receipt
- REST API returns JSON and supports webhook notifications
- Tracks status and retries failed transmissions automatically
Where it doesn't
- No free plan is available
- The product is API-only rather than a standalone fax application
- Pay-as-you-go pricing may require usage forecasting
Our verdict on Sinch Fax API
Sinch Fax API is a REST-based cloud service for developers building fax workflows into business applications. It supports sending outbound faxes, receiving inbound faxes, retrieving fax status, and tracking completion. Webhook notifications can report incoming and completed faxes, while JSON responses fit applications that need structured API data. The service is positioned for business workflows in healthcare, legal, finance, insurance, and real estate, with pay-as-you-go usage rather than a recurring subscription plan.
Its strongest technical fit is workflow automation. Basic and OAuth2 authentication support different integration requirements, and automatic retries address failed transmissions without requiring every retry decision to be handled by application logic. Fax logs and media remain accessible for 13 months, giving teams a defined period for reviewing transmission history and related files. These features make the product suited to applications that need delivery visibility, inbound event handling, and a programmable way to connect faxing with existing business processes.
The main trade-off is focus: Sinch Fax API is designed for API-based implementation, so it is a better choice for development teams than for organizations seeking a user-facing fax workspace. The published offering uses usage-based pricing and does not provide a free plan, which makes expected fax volume an important purchasing consideration. Choose it when inbound and outbound faxing, REST integration, status tracking, webhooks, authentication options, retries, and retained logs matter. Consider an alternative if the priority is a standalone application or a free product tier.
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Sinch Fax API pricing
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Sinch Fax API fact sheet
| Free plan | No |
|---|---|
| Paid from | Not verified |
| Inbound faxing | Yes |
| Outbound faxing | Yes |
| Delivery tracking | Yes |
| Webhook events | Yes |
| API protocol | Rest |
| Included pages | Not verified |
| Deployment | Cloud |
| Compliance & security | SOC 2, GDPR, HIPAA |
| Support | Tickets, Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Paid (source) |
| Website | sinch.com |
| Facts checked | 20 Sep 2026 |
Alternatives to Sinch Fax API
- Telnyx Fax APIA low per-page REST fax API with inbound, outbound, tracking, and webhook support.9.4
- PhaxioA feature-rich fax API for sending, receiving, tracking, and routing documents.9.2
- FaxxingA practical free-start fax API with inbound support, signed webhooks, and usage-based pricing.9.1
See all Sinch Fax API alternatives →
Sinch Fax API vs the competition
- Sinch Fax API vs Telnyx Fax API
- Sinch Fax API vs Phaxio
- Sinch Fax API vs Faxxing
- Sinch Fax API vs OpenText Core Fax Management API
- Sinch Fax API vs Documo Fax API
- Sinch Fax API vs Openfax Cloud Fax API
Compare Sinch Fax API with any tool side by side →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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