Sinch Fax API
Stockholm, Sweden
What it is
Sinch Fax API is a cloud-based service for sending and receiving faxes through software integrations. Its REST API supports inbound and outbound faxing, delivery tracking, and webhook notifications for incoming or completed faxes. Developers can authenticate with Basic or OAuth 2 and use Node.js, Java, .NET, or Python SDKs. Supported content formats include DOC, DOCX, PDF, TIF, JPG, TXT, PNG, URLs, and HTML. A customer portal displays fax times and status and provides controls for users, groups, roles, and permissions. The service offers routing and retries for failed transmissions; customers can select local or toll-free numbers or bring their own. Sinch states that U.S. fax processing has redundant infrastructure and 99.999% uptime, and that the service supports HIPAA, SOC 2, and GDPR compliance needs. When storage is enabled, fax logs and media are kept for 13 months before deletion. A free Sinch Build Dashboard account is required to get started, and signup includes a free virtual number for testing. Pay-as-you-go is $0.05 per page; pricing is also available on request.
For and against
For
- Supports inbound and outbound faxing with delivery tracking.
- Offers automatic retries and intelligent routing.
- Supports DOC, DOCX, PDF, TIF, JPG, TXT, PNG, URL, and HTML.
- Provides a portal for status and permission management.
- Pay-as-you-go rate is $0.05 per page.
Against
- Each service can have only one webhook at a time.
- Storage-enabled fax logs and media are deleted after 13 months.
- Production pricing is available on request.
The verdict
Sinch Fax API combines fax transmission, tracking, and management tools for integration into business workflows. Its single-webhook limit per service and on-request pricing are worth considering.
Who it suits
It suits startups and established companies that need fax workflows in areas such as healthcare, legal, finance, insurance, or real estate. Teams can use it through an API and manage fax activity in a web portal.
Plans and prices
Pay-as-you-go
Flat rate per page; no hidden charges stated
Read 4 Oct 2026 · sinch.com
On the record
- 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.developers.sinch.com · read 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.sinch.com · read 4 Oct 2026
- File formats
- The product page lists DOC, DOCX, PDF, TIF, JPG, TXT, PNG, URL, and HTML content as supported formats.sinch.com · read 4 Oct 2026
- 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.developers.sinch.com · read 4 Oct 2026
- Integration
- Sinch documents a Zapier integration with an inbound fax trigger and a send-a-fax action.developers.sinch.com · read 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.developers.sinch.com · read 4 Oct 2026
- Intended users
- Sinch describes the API for startups and established companies, with examples spanning healthcare, legal, finance, insurance, and real estate.sinch.com · read 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.sinch.com · read 4 Oct 2026
- Reliability
- Sinch states that its network has 99.999% uptime and redundant infrastructure for fax processing in the U.S.sinch.com · read 4 Oct 2026
- Routing and retries
- The service offers intelligent routing and automatic retries for failed fax transmissions.sinch.com · read 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.sinch.com · read 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.developers.sinch.com · read 4 Oct 2026
- What it does
- Sinch Fax API is a cloud-based service for securely sending and receiving faxes through an API.sinch.com · read 4 Oct 2026
