By Sarah Martinez · Published April 21, 2026 · Updated June 8, 2026 · 9 min read
Quick Answer: An internet fax service converts your documents into fax-compatible format and delivers them to any fax number worldwide — without a machine, a phone line, or paper. mFax.to is the fastest way to get started on mobile.
An internet fax service makes traditional faxing work entirely over the web. Instead of a physical fax machine dialing a phone number, your document travels as encrypted data to a cloud gateway, which completes the delivery to any fax number on earth. No phone line, no machine, no ink cartridges.
Internet fax services handle billions of pages every year. Healthcare, legal, insurance, and government organizations rely on them for document delivery that is legally recognized, auditable, and more secure than email. For individuals, they replace the frustrating trip to UPS or FedEx with a two-minute process from any smartphone.
This guide covers how internet faxing works under the hood, what features separate good services from bad ones, HIPAA compliance requirements, and how to pick the right plan for your situation.
What Is an Internet Fax Service?
An internet fax service is a cloud platform that handles fax transmission over the internet. You upload a document, enter the recipient's fax number, and click send. The service converts your document into fax-compatible format (TIFF or multi-page PDF) and routes it through the public telephone network to reach any fax machine or online fax inbox.
Receiving works in reverse. The service assigns you a virtual fax number. Anyone who faxes that number reaches the service's gateway, which converts the incoming transmission to a PDF and delivers it to your email, app, or web dashboard.
The result: faxing works exactly as it always has for the other party. For you, there is no hardware, no phone line, and no trips to the office.
Why Fax Still Matters in 2026
Over 17 billion faxes are sent annually worldwide. Hospitals, law firms, insurance companies, and government agencies still require fax for binding document delivery because it is legally recognized, time-stamped, and produces a verifiable transmission record that email cannot match.
How Internet Faxing Works
Internet fax services use one of two technical approaches:
T.38 Real-Time Fax
T.38 is the ITU standard for sending fax signals over IP networks in real time. The gateway demodulates the fax audio into structured data packets, transmits them over the internet with built-in redundancy, and re-modulates at the receiving end. The recipient's fax machine never knows the signal traveled over the internet.
T.38 is the most reliable protocol for business faxing. It qualifies for HIPAA's conduit exemption — meaning the provider may not need to sign a Business Associate Agreement (BAA) because the data is not stored, only passed through.
Store-and-Forward Cloud Fax
Most consumer internet fax services use store-and-forward: the document is held on the provider's servers while it waits for delivery. This method is more flexible — you can schedule faxes, retry failed transmissions automatically, and access your fax history. The trade-off is that the provider becomes a data custodian, which requires a signed BAA for HIPAA purposes.
Three Ways to Send
| Method | How It Works | Best For |
|---|---|---|
| Web portal | Log in, upload file, enter fax number, send | Desktop users, one-off faxes |
| Email-to-fax | Attach file to email, send to [faxnumber]@provider.com | Power users, workflow automation |
| Mobile app | Scan or upload from phone, send in the app | Remote workers, occasional use |
| API / integration | Programmatic fax via REST API | High-volume, automated workflows |
Internet Fax vs. Traditional Fax Machine
The cost difference between a traditional fax setup and an internet fax service is significant — and it compounds over time.
| Traditional Fax Machine | Internet Fax Service | |
|---|---|---|
| Equipment | $150–$600 upfront | None |
| Dedicated phone line | Required ($25–$50/mo) | Not needed |
| Paper & ink | Ongoing cost | None |
| Send from | Office only | Any device, anywhere |
| Receive faxes | Machine must be on and loaded | Delivered to email/app 24/7 |
| Document storage | Paper piles up | Cloud storage, searchable PDFs |
| HIPAA compliance | Complex, hardware-dependent | Available from providers |
| Estimated monthly cost | $50–$150/mo total | $8–$50/mo |
For most businesses, switching to an internet fax service cuts faxing costs by 50–80% while improving reliability and accessibility. The break-even point on a traditional fax machine — factoring in phone line, paper, and ink — is rarely more than two or three months of service subscription.
How to Send a Fax Over the Internet
Choose a Service
Sign up for an internet fax service. For quick mobile sending, mFax.to requires no subscription — pay per fax. For regular business use, choose a monthly plan that includes a dedicated virtual fax number.
Prepare Your Document
PDF format works with every internet fax service. If you have a Word document or image, convert it first using a free tool like the mFax document converter. Most services also accept DOCX, JPG, and PNG directly.
Enter the Fax Number
Include the country code and area code: +1 212 555 0100 for US numbers. For international faxing, check the service's supported countries — not all providers route globally. Some charge extra per-page fees for international destinations.
Add a Cover Sheet (If Needed)
Many professional and healthcare faxes require a cover sheet listing sender, recipient, date, and page count. Use the free mFax cover sheet generator to create one instantly — no sign-up required.
Send and Confirm
Click send. You'll receive a delivery confirmation — a timestamped transmission report with the recipient fax number. Most services email the confirmation automatically. Keep it for your records, especially for legal or medical documents.
Key Features to Look For
Not all internet fax services deliver the same experience. Here is what actually matters when evaluating options.
Virtual Fax Number
You need a dedicated fax number to receive faxes. Most plans include one. Look for local numbers matching your area code and toll-free options. Number porting lets you transfer your existing fax number to the new provider — verify this is supported before you switch. See our full guide to virtual fax numbers for the porting process.
Page Limits and Overage Fees
Plans come with a monthly page allotment. Overages can be expensive — some providers charge $0.10–$0.25 per extra page. Count your realistic monthly volume before picking a plan. If you fax infrequently, pay-as-you-go beats a subscription.
HIPAA Compliance
For healthcare, legal, and financial services, HIPAA compliance is not optional. A compliant provider must use end-to-end encryption, maintain audit logs, store documents in a HIPAA-eligible environment, and sign a BAA. See the HIPAA compliant fax guide for the complete checklist. Free tiers almost never qualify.
International Coverage
If you send faxes outside the US, verify coverage before subscribing. Some providers reach 180+ countries; others are US/Canada only. International per-page rates vary widely — confirm pricing for your specific destinations.
Mobile App Quality
For mobile-first faxing, app quality matters as much as the underlying service. The app should let you scan physical documents with your phone camera, upload from cloud storage (Google Drive, Dropbox, iCloud), and receive push notifications for incoming faxes.
Cloud Storage Integrations
Business users benefit from integrations with Google Drive, Dropbox, OneDrive, Salesforce, and practice management software. If you fax frequently from a specific workflow, confirm the integration exists before committing.
Top Internet Fax Services Compared
| Service | Best For | Price | Free Trial | HIPAA |
|---|---|---|---|---|
| mFax.to | Mobile & occasional use | Pay-per-fax or plans from $9.99/mo | Yes | Business plan |
| eFax | Enterprise teams | From $16.95/mo | No | Yes |
| Fax.Plus | International faxing | Free tier / from $7.99/mo | Free tier | Yes |
| RingCentral Fax | Unified communications | Add-on to RingCentral plan | Trial available | Yes |
| MetroFax | High-volume business | From $8.30/mo (500 pages) | No | Yes |
For a full breakdown with hands-on testing notes, pricing tiers, and pros/cons for each service, see our best internet fax services comparison.
Internet Fax and HIPAA Compliance
Healthcare organizations must treat all fax transmissions containing patient information as Protected Health Information (PHI). A standard fax machine on a shared phone line almost certainly fails modern HIPAA requirements. Internet fax can be HIPAA compliant — but only under specific conditions.
HIPAA Requires a BAA
If your internet fax service stores copies of your faxes (most do), the provider becomes a business associate under HIPAA. You must have a signed Business Associate Agreement (BAA) before transmitting any PHI. A BAA is a legal contract — not just a checkbox in an account settings panel.
The minimum requirements for HIPAA-compliant internet faxing:
- Encryption in transit: TLS 1.2 or higher for all transmissions
- Encryption at rest: Documents stored on provider servers must be encrypted at the storage layer
- Access controls: Role-based permissions, no shared logins, MFA enforced
- Audit logging: Every send and receive logged with user identity, timestamp, and recipient
- BAA: Signed agreement in place before any PHI is transmitted
mFax Business meets all of these requirements and includes BAA signing as part of the onboarding process. Plans start at about $9/mo (billed annually).
How to Choose the Right Internet Fax Service
Your ideal plan depends on volume, use case, and compliance needs.
For occasional personal use (1–10 faxes/month): Pay-as-you-go is the most cost-effective option. No monthly fee, no commitment. mFax.to lets you send immediately from the app — upload, enter a fax number, done.
For regular individual use (10–50 faxes/month): A personal subscription plan ($8–$15/mo) makes more sense. Look for a plan that includes a dedicated virtual fax number so you can receive faxes as well as send them.
For small business teams (50–200 faxes/month): Prioritize team accounts, shared inbox, and delivery receipts. mFax Business and similar business plans include dedicated fax numbers per user and a centralized dashboard.
For healthcare or legal (compliance-critical): HIPAA compliance is non-negotiable. Require a BAA, verify encryption specifications, and test the audit log before signing up. The extra $10–$20/mo for a compliant plan is a legal requirement, not an upgrade.
For enterprise (500+ pages/month): Look for volume pricing, SLA guarantees, REST API access, and dedicated support. MetroFax and eFax offer enterprise tiers with discounted per-page rates at scale.
Receiving Faxes Over the Internet
Incoming faxes from any traditional fax machine reach your virtual fax number and are automatically converted to PDF, then delivered to:
- Email inbox: As a PDF attachment — searchable, archivable, easy to forward
- Mobile app: Push notification when a fax arrives, viewable immediately
- Web dashboard: Full inbox for teams, with filters and search
For setup details, see our guide on how to receive faxes by email.
Fax Archiving
Most internet fax services store 30–365 days of fax history in the cloud. For legal and healthcare faxes, verify the retention period meets your record-keeping requirements before committing to a plan.
Common Questions
Do I need a landline to use an internet fax service?
No. Internet fax services work entirely over your existing internet connection — broadband, Wi-Fi, or cellular. The provider's servers handle all the phone network routing. You never need a phone jack.
Can I fax internationally with an internet fax service?
Yes, but coverage varies by provider. Some services support 180+ countries while others are limited to the US and Canada. Always verify your destination countries before subscribing, and check whether international rates are included in the plan or billed per page as an overage.
How secure is internet fax compared to email?
More secure for regulated industries. Internet fax transmissions are encrypted in transit, access is controlled at the account level, and every transmission is logged with a timestamp. Email lacks native encryption and leaves documents accessible in inbox archives indefinitely. For healthcare, legal, and financial documents, fax remains the preferred transport because the compliance framework is legally established.
Can I send a free fax over the internet?
Some services offer a free tier with limited monthly pages — Fax.Plus offers 10 free pages per month. For truly free faxing, see our guide to free internet fax options. Keep in mind free tiers exclude HIPAA compliance and dedicated fax numbers.
Send Your First Internet Fax
An internet fax service eliminates the hardware, the phone line, the paper, and the ink — while keeping full compatibility with every fax machine and organization that still requires fax.
For personal faxing, download the mFax app and send in under 2 minutes — upload a PDF, enter a fax number, and tap send. No subscription required.
For business teams, mFax Business gives your team dedicated virtual fax numbers, HIPAA-ready infrastructure, shared inbox, and full audit logging — starting at about $9/mo. Rather than forcing you into rigid fixed tiers, mFax Business is fully customizable: build your own plan by picking the exact seats and monthly pages you need with a live calculator, and pay only for what you actually use.