Sinch Fax API
Sinch Fax API sends and receives faxes through a cloud service, with REST API access for integrating fax workflows into software.
What Sinch Fax API is
Sinch Fax API sends and receives faxes through a cloud service, with REST API access for integrating fax workflows into software. It supports DOC, DOCX, PDF, TIF, JPG, TXT, PNG, URL, and HTML content, plus delivery tracking and webhooks for arriving or completed faxes. Authentication can use Basic or OAuth 2. Automatic retries and intelligent routing are available for failed transmissions. When storage is enabled, fax logs and media are kept for 13 months before deletion. The customer portal displays fax times and status and supports management of users, groups, roles, and permissions. Customers can select local or toll-free numbers or bring their own. Sinch describes support for HIPAA, SOC 2, and GDPR compliance needs, and says its U.S. fax network has 99.999% uptime with redundant infrastructure. A free Sinch Build Dashboard account is required to start, and signup includes a virtual number for testing. Pay-as-you-go is $0.05 per page; other pricing is available on request.
Good
- Supports inbound and outbound faxing with delivery tracking.
- Automatic retries and intelligent routing for failed transmissions.
- Portal manages users, groups, roles, and permissions.
- Supports DOC, PDF, images, text, URLs, and HTML.
- Listed Pay-as-you-go rate is $0.05 per page.
Watch out
- Pricing beyond the listed rate is on request.
- Zapier allows only one inbound fax trigger per service.
- Stored fax logs and media are deleted after 13 months.
- Concurrent call limit is 10 calls.
Who it suits
It suits startups and established organizations in areas such as healthcare, legal services, finance, insurance, and real estate that need fax workflows in software. Developers can use its REST API and SDKs for Node.js, Java, .NET, and Python.
Verdict
Sinch Fax API combines fax transmission, tracking, and number options with REST integration. Check the one-webhook-per-service limit and the on-request pricing before planning an integration.
Plans and prices
From Sinch Fax API's own pricing page, checked 4 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Pay-as-you-go | $0.05, paid once | Flat rate per page; no hidden charges stated · per page |
The facts
Each one read from Sinch Fax API's own pages, with the date it was checked.
What it does
- 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.checked 4 Oct 2026
- Dashboard
- The customer portal can show fax send and receive times and status, and lets users manage users, groups, roles, and permissions.checked 4 Oct 2026
- File formats
- The product page lists DOC, DOCX, PDF, TIF, JPG, TXT, PNG, URL, and HTML content as supported formats.checked 4 Oct 2026
- Integration
- Sinch documents a Zapier integration with an inbound fax trigger and a send-a-fax action.checked 4 Oct 2026
- Integration limit
- A Fax API service can have only one webhook at a time, which allows one inbound fax trigger per service in Zapier.checked 4 Oct 2026
- Intended users
- Sinch describes the API for startups and established companies, with examples spanning healthcare, legal, finance, insurance, and real estate.checked 4 Oct 2026
- 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.checked 4 Oct 2026
- Reliability
- Sinch states that its network has 99.999% uptime and redundant infrastructure for fax processing in the U.S.checked 4 Oct 2026
- Routing and retries
- The service offers intelligent routing and automatic retries for failed fax transmissions.checked 4 Oct 2026
- Security
- Sinch says the service supports HIPAA, SOC 2, and GDPR compliance needs, and describes advanced encryption and secure transmission methods for healthcare data.checked 4 Oct 2026
- Support
- Sinch offers product contact through its sales team and developer documentation, and the API reference directs users with questions to the support portal.checked 4 Oct 2026
- What it does
- Sinch Fax API is a cloud-based service for securely sending and receiving faxes through an API.checked 4 Oct 2026
The company
- Founded
- 2008checked 28 Sep 2026
- Headquarters
- Stockholm, Swedenchecked 28 Sep 2026
Money
- 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.checked 4 Oct 2026
