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SPECIFICTION
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Sinch Fax API

sinch.com

WebAPI
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Spec score 7.2 #22 of 26 in Fax APIs

What it is

Sinch Fax API is a cloud service for sending and receiving faxes through a REST API. It supports delivery tracking and webhooks for incoming or completed faxes, with Basic or OAuth 2 authentication. If storage is enabled, fax logs and media remain available for 13 months before deletion. Listed formats include DOC, DOCX, PDF, TIF, JPG, TXT, PNG, URLs, and HTML. A customer portal shows fax status and send or receive times, and provides controls for users, groups, roles, and permissions. Sinch describes intelligent routing and automatic retries for failed transmissions, and says its U.S. fax-processing network has 99.999% uptime and redundant infrastructure. Customers can select local or toll-free numbers or bring their own; the infrastructure is described as scalable for high volumes. The service supports stated HIPAA, SOC 2, and GDPR compliance needs and secure transmission for healthcare data. A free Sinch Build Dashboard account is required to start, and signup includes a free virtual number for testing. Pay-as-you-go costs $0.05.

Spec sheet

What it does
Sinch Fax API is a cloud-based service for securely sending and receiving faxes through an API.Read 4 Oct 2026 · sinch.com
Intended users
Sinch describes the API for startups and established companies, with examples spanning healthcare, legal, finance, insurance, and real estate.Read 4 Oct 2026 · sinch.com
Security
Sinch says the service supports HIPAA, SOC 2, and GDPR compliance needs, and describes advanced encryption and secure transmission methods for healthcare data.Read 4 Oct 2026 · sinch.com
Support
Sinch offers product contact through its sales team and developer documentation, and the API reference directs users with questions to the support portal.Read 4 Oct 2026 · developers.sinch.com
Headquarters
Stockholm, SwedenRead 28 Sep 2026 · sinch.com
Founded
2008Read 28 Sep 2026 · sinch.com
API and retention
The Fax REST API supports Basic or OAuth 2 authentication, webhooks for arriving or completed faxes, and—if storage is enabled—retains fax logs and media for 13 months before deletion.Read 4 Oct 2026 · developers.sinch.com
Dashboard
The customer portal can show fax send and receive times and status, and lets users manage users, groups, roles, and permissions.Read 4 Oct 2026 · sinch.com
File formats
The product page lists DOC, DOCX, PDF, TIF, JPG, TXT, PNG, URL, and HTML content as supported formats.Read 4 Oct 2026 · sinch.com
Free account
The getting-started guide says Fax API use requires a free Sinch Build Dashboard account and that signup includes a free virtual number for testing.Read 4 Oct 2026 · developers.sinch.com
Integration
Sinch documents a Zapier integration with an inbound fax trigger and a send-a-fax action.Read 4 Oct 2026 · developers.sinch.com
Integration limit
A Fax API service can have only one webhook at a time, which allows one inbound fax trigger per service in Zapier.Read 4 Oct 2026 · developers.sinch.com
Numbers and scale
Customers can choose from millions of local or toll-free numbers or bring their own, and Sinch says its infrastructure scales for high fax volumes.Read 4 Oct 2026 · sinch.com
Reliability
Sinch states that its network has 99.999% uptime and redundant infrastructure for fax processing in the U.S.Read 4 Oct 2026 · sinch.com
Routing and retries
The service offers intelligent routing and automatic retries for failed fax transmissions.Read 4 Oct 2026 · sinch.com

Plans and prices

Pay-as-you-go $0.05, paid once per page Flat rate per page; no hidden charges stated Read 4 Oct 2026 · sinch.com

Every Sinch Fax API plan and price →

Strong points and limits

Strong points

  • Supports inbound and outbound faxing with delivery tracking.
  • Retries failed transmissions automatically.
  • Accepts a broad range of document and image formats.
  • Offers local and toll-free numbers or number porting.
  • SDK languages include Node.js, Java, .NET, and Python.

Limits

  • Pricing is also described as available on request.
  • A service can have only one webhook at a time.
  • Enabled storage deletes fax logs and media after 13 months.
  • Concurrent call limit is 10 calls.

Who it suits

It suits startups and established companies that need API-based inbound and outbound faxing, including organizations in healthcare, legal, finance, insurance, or real estate. The portal and webhooks also suit teams that need status visibility or fax-event integration.

Verdict

Sinch Fax API combines REST-based fax handling with tracking, routing, retries, and a portal for status and access management. Its listed rate is $0.05, while one-webhook-per-service is a relevant integration constraint.

Where Specifiction places it

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