Microsoft 365 Fax (via third‑party connectors) lets users send and receive faxes from Outlook, but many organisations look for dedicated fax‑as‑a‑service platforms that offer deeper API support, stronger security, and broader integration options. Below are 20 leading fax‑service solutions that can replace or complement Microsoft 365 Fax through native apps, Zapier/Power Automate connectors, or robust REST APIs.
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Enterprise‑grade cloud fax with Outlook add‑in, API, and Zapier connector; supports HIPAA compliance, digital signatures, and mobile apps.
Integrated with RingCentral’s UC suite; offers Outlook plug‑in, REST API, and Power Automate connector for automated fax workflows.
Scalable cloud fax platform with Microsoft Teams & Outlook add‑ins, Zapier integration, and a full‑featured API; GDPR‑compliant.
Business fax service with Outlook integration, API access, and Zapier support; includes secure storage and audit logs.
Secure fax‑as‑a‑service focused on healthcare; offers HIPAA‑compliant API, Power Automate connector, and Outlook plug‑in.
Cloud fax with Outlook add‑in, API, and Zapier integration; provides unlimited inbound/outbound faxes for unlimited users.
User‑friendly web fax with Google Workspace & Microsoft 365 integration via Zapier; includes e‑signature and encrypted storage.
Enterprise fax solution with robust API, Microsoft Power Automate connector, and on‑premises or cloud deployment options.
Industry‑standard fax server with cloud‑ready API, Outlook integration, and Power Platform connectors for automated workflows.
Secure fax API with SDKs for .NET, Java, and Node; integrates with Microsoft Flow/Power Automate via custom connector.
Low‑cost virtual fax number with Outlook add‑in, Zapier support, and API for sending/receiving faxes programmatically.
Mobile‑first fax service offering a temporary fax number, Outlook integration via Zapier, and a simple REST API.
Secure cloud fax platform with end‑to‑end encryption, Outlook add‑in, Power Automate connector, and compliance certifications (HIPAA, GDPR).
Online fax service with Outlook plug‑in, Zapier integration, and API; includes digital signature and document tracking.
Business fax service offering a Microsoft Teams connector, Outlook integration, and a REST API for bulk faxing.
Cloud fax solution with API, Power Automate custom connector, and Outlook add‑in; focuses on secure transmission for legal firms.
Hybrid fax server with cloud option; provides Outlook integration, SOAP/REST API, and Power Platform connectors.
Enterprise fax management with robust API, Microsoft Teams & Outlook integration, and compliance features for regulated industries.
Free web‑based fax service with limited daily sends; integrates via Zapier for simple automation, suitable for low‑volume needs.
Legacy cloud fax platform offering Outlook add‑in, API, and Zapier connector; now rebranded under eFax corporate suite.