What Is a VoIP Softphone? How It Works and Why Businesses Use It

If you have looked into switching your business to VoIP, you have probably come across the word softphone. It sounds more technical than it is. This guide explains what a softphone is, how it works, what the advantages and disadvantages are compared to a physical desk phone, and when each option makes sense for a business.

What Is a Softphone?

A softphone is a software application that lets you make and receive voice calls over the internet. Instead of a physical handset plugged into a phone line or a VoIP adapter, the phone lives entirely on your device — a computer, a laptop, a smartphone, or a tablet.

It replicates the functionality of a desk phone. You get a dial pad, the ability to answer and end calls, hold, transfer, conference calling, voicemail, and any other features your VoIP plan supports. The only difference is that there is no hardware to buy, install, or maintain. You download an application and log in.

A desktop softphone runs on a Windows PC or Mac. A mobile softphone — often called a mobile app — runs on iOS or Android. Many businesses use both at the same time, giving each user the flexibility to take calls from a computer at a desk or from a phone while out of the office.

How Does a Softphone Work?

The underlying technology is straightforward. When you make a call using a softphone, the application connects to your VoIP provider over your internet connection using a protocol called SIP — Session Initiation Protocol. SIP handles the signalling: it establishes the call, keeps it running, and ends it when either party hangs up.

Your voice is captured by a microphone, converted into digital data packets, and sent across the internet to the person you are calling. At the other end, those packets are reassembled and converted back into audio. The whole process happens fast enough that it sounds like a normal phone call.

The softphone does not care what type of internet connection you are on, as long as it is stable and reasonably fast. Broadband, 4G, and 5G all work. The minimum bandwidth required per call is low — typically around 100 kbps — so even a basic connection can handle multiple simultaneous calls without problems.

Desktop Softphones

A desktop softphone installs on your computer like any other application. Once you log in with your VoIP credentials, it registers with your provider and you are ready to make and receive calls.

On screen, you get a dial pad and a call window. Incoming calls appear as a notification or pop-up. You can click to dial from a contact list or type a number directly. Transfers, call holds, and conference calls all work through the interface rather than physical buttons.

For audio, you connect a headset. A dedicated headset — rather than relying on your laptop's built-in microphone and speakers — makes a meaningful difference to call quality, particularly in open-plan offices or anywhere with background noise. A corded USB headset typically gives the most consistent audio because it avoids the interference that can occasionally affect Bluetooth connections, though a good Bluetooth headset is perfectly adequate for most situations.

Desktop softphones work well for anyone who spends a significant part of their day at a computer. The workflow integrates naturally — you are already at your screen, and calls arrive and are managed in the same environment.

Mobile Softphones

A mobile softphone is the same technology running on a smartphone. You install the app from the App Store or Google Play, log in with your VoIP credentials, and your business phone number works from your mobile.

This matters for a specific reason: when you call out, your business DDI number appears on the recipient's caller ID, not your personal mobile number. Incoming calls to your business number ring the app. To the caller, there is no difference between reaching you on a desk phone or on the app.

For remote workers, people who travel, or anyone who moves between locations during the working day, a mobile softphone means they are reachable on their business number without being tied to a desk. They do not need to give out a personal mobile number or ask callers to try multiple numbers.

Advantages of Softphones Over Desk Phones

No hardware cost. There is nothing to buy, ship, or install. A softphone costs nothing beyond the VoIP plan itself.

Not tied to a desk. A desk phone only works where it is installed. A softphone works anywhere you have an internet connection or a mobile signal.

Fast to set up. Adding a new user means sending them login credentials and a link to download the app. There is no waiting for hardware to arrive.

Easy to scale. If your team grows, you add users on your account. No hardware orders, no installation visits, no delays.

Built for remote and hybrid teams. Softphones work identically whether your team is in an office, working from home, or spread across the country. It is not a workaround — it is how the system is designed.

Call recording works the same. Features like call recording, voicemail, and auto-attendant apply to softphone calls just as they do to calls taken on a desk phone.

Disadvantages and Considerations

Depends on a charged device and a working connection. A desk phone on a PoE switch keeps working if a laptop battery dies. With a softphone, if the device is off or has no signal, calls cannot be received on that device.

Battery drain on smartphones. Running a VoIP app in the background uses more battery than a phone sitting idle. Heavy users may find themselves reaching for a charger more often.

Audio quality depends on your microphone. A desk phone has a built-in handset designed for call audio. A softphone passes that responsibility to whatever microphone you are using. A decent headset resolves this entirely, but it is worth factoring in if you have not budgeted for one.

Some people prefer a physical handset. This is not irrational. Picking up a handset and putting it down is a natural action that some users find clearer and more comfortable, particularly in high-volume call environments.

When Desk Phones Still Make Sense

Softphones are sufficient for the majority of business users, but there are situations where a physical desk phone is still the practical choice.

Reception desks where someone is answering calls continuously throughout the day often benefit from a dedicated handset. Call centre environments with agents making and receiving dozens of calls per shift may find that physical phones reduce fatigue and errors. Any role where the person is always at the same desk and the phone is their primary tool all day is a reasonable candidate for hardware.

For everyone else — field sales, remote employees, consultants, office staff who also move around — a softphone handles everything a desk phone does without the limitations.

Softphone and Mobile App on VoIPninjas

VoIPninjas includes both a desktop softphone and a mobile app on the Samurai plan (from £14.99 per user per month) and the Shogun plan (from £24.99 per user per month). The apps run on iOS and Android.

The full feature set applies through both apps: call recording, call transfers, voicemail, DDI numbers, and auto-attendant all work the same way whether a call is taken on a computer or a mobile. There is no reduced functionality on the app compared to a desk setup.

All plans run on a 28-day rolling basis with no contract. You can start a free 14-day trial without entering card details, and most customers are live within 10 working days.

What Headset Should You Use?

Any USB or Bluetooth headset with a built-in microphone will work with a desktop softphone. For users who take a high volume of calls at a desk, a corded USB headset — something from Jabra, Poly, or Sennheiser's business range — gives the most reliable audio quality day to day. Bluetooth headsets are convenient but check the battery and ensure pairing stays consistent with your specific computer.

For mobile softphone users, standard wired earphones with a microphone are fine for most calls. If you regularly take calls in noisy environments, a headset with active noise cancellation on the microphone makes a noticeable difference to the experience for the person on the other end.

Try VoIPninjas free for 14 days — no card required, no contract. Get a full UK phone system including DDI numbers, call recording, and the mobile app. Most customers are live within 10 working days. Start your free trial

Frequently Asked Questions

Can I use a softphone on any internet connection?

Yes. A softphone works on any broadband, 4G, or 5G connection. You do not need a dedicated business line or any special network setup. A stable connection with at least a few megabits per second is enough for clear calls. If you are using public Wi-Fi, call quality may vary depending on network congestion.

Will my business number show up when I call from the app?

Yes. When you call out using the VoIPninjas mobile app, your business DDI number appears on the recipient's caller ID. Your personal mobile number is not displayed. This applies regardless of whether you are calling from the desktop softphone or the mobile app.

Can I use a softphone and a desk phone on the same number?

Yes. A VoIP number can ring on multiple devices simultaneously or in a set sequence. You can have your office desk phone and your mobile app both registered to the same number. When a call comes in, both ring and whoever answers first takes the call.

Do I need IT support to set up a softphone?

No. The setup process is straightforward: download the app, enter the credentials provided by your VoIP provider, and you are ready. Most users can do this themselves in a few minutes. If you run into any problems, VoIPninjas support is available by phone on 0330 043 2388.