A softphone is software that turns a computer, a browser tab or a smartphone into a business phone. It places and receives calls over the internet using voice over IP, with a company phone number and no physical desk phone: a headset with a microphone is all you need.
The name is short for software phone, as opposed to a hardphone, the desk set. Softphones went mainstream with cloud phone systems and the retirement of copper landlines: nearly every business phone system sold today ships with one, and many sales teams no longer own a single desk phone. This guide explains what a softphone is, how it works, how it differs from an IP phone and from your mobile’s built-in dialer, and what to check when the softphone is the tool your reps sell with.
What is a softphone, exactly?
A softphone reproduces on screen what a desk phone does: a keypad, answer and hang-up buttons, call history, contacts, hold, transfer. The difference is the form factor. Instead of a dedicated device, it is software running on hardware you already have.
A softphone needs four things to work:
- A device: a computer running Windows, macOS or Linux, or an iOS or Android smartphone.
- Software: an installed app, a browser tab, or a mobile app.
- A phone service account with a VoIP carrier or a cloud platform, which provides the number and connects calls to the public phone network.
- A steady internet connection and an audio device: wired headset, Bluetooth headset, or built-in mic and speakers.
Point 3 is the one people miss. A softphone is not a carrier. Some programs are bare calling clients: you type in SIP credentials from a carrier and they simply place calls. Others come from the platform that also provides the number: you sign in with your account and everything is already set up. That second model covers almost every business phone system on the market today.
How does a softphone work?
Like any VoIP system, a softphone breaks the voice into small data packets and sends them over the internet. Three building blocks do the work.
Signaling. This sets up the call, makes it ring, transfers it and ends it. The standard protocol is SIP (Session Initiation Protocol). A desktop softphone or a mobile app typically speaks SIP with its carrier’s servers.
Media transport. Once the call is up, audio travels in a separate stream, usually RTP (Real-time Transport Protocol), ideally encrypted as SRTP.
The codec. It compresses the voice on the way out and rebuilds it on arrival. G.711, the legacy telephony codec, carries 64 kbps of voice, which comes to roughly 100 kbps per direction once network headers are added. Opus, a newer codec, adapts to the quality of the connection.
Softphones in the browser
A softphone can also run with nothing to install, right in Chrome, Edge, Firefox or Safari. That is possible thanks to WebRTC, a W3C and IETF standard that gives the browser access to the microphone and speakers and streams voice in real time. The W3C published it as an official Recommendation in January 2021, and IETF RFC 7874 requires compliant browsers to support at least the Opus and G.711 codecs.
For the user, the result is simple: open a page, allow the microphone, start calling. No software rollout by IT, no updates to push to every laptop.
Softphone vs IP phone vs mobile phone app
Three ways of calling coexist in a company on VoIP. They look alike, but they solve different problems.
| Softphone (computer or browser) | IP phone (desk set) | Mobile’s built-in phone app | |
|---|---|---|---|
| Form | Software on a computer or a browser tab | Dedicated physical device | Built into the smartphone |
| Network | Internet (VoIP) | Internet or local network (VoIP) | Mobile carrier network |
| Caller ID shown | The platform’s business number | The platform’s business number | Your mobile number |
| Hardware cost | A headset | A phone per seat | The phone itself |
| Mobility | Follows the user to any connected computer | Fixed | Full |
| Calls logged to the CRM | Yes, if the platform integrates | Depends on the platform | No, unless typed in by hand |
| Best for | Sales reps, remote work, distributed teams | Reception, conference rooms, shared desks | Personal use |
A fourth case muddies the discussion: the softphone app installed on a smartphone. It runs on the same device as the built-in phone app, but it calls over the internet (Wi-Fi or mobile data) with the business number. A rep can keep a personal number in the built-in app and a work number in the softphone app, on a single phone.
For the broader comparison between VoIP and legacy lines, including migration, see our guide to VoIP vs traditional phone systems.
Desktop app or browser?
Both computer formats have their strengths.
An installed app lives outside the browser. It keeps running when every tab is closed, can ring in the foreground, and sometimes integrates with system shortcuts. On the other hand, it needs installing and updating on every machine, which becomes a burden as the team grows or when IT locks down laptops.
A browser softphone opens from a web address. It runs on any recent computer, updates itself, and sits naturally next to the other browser tools reps already use, like the CRM. Its constraint: the tab must stay open to receive calls, and some browsers’ power-saving features can put an idle tab to sleep.
For a sales team that spends the day in the browser, a web softphone is often the simplest choice. For a front desk that must ring every time, an installed app or an IP phone remains safer.
What to check when the softphone is used to sell
A basic softphone places calls. A sales rep needs more. Here is what makes the difference in prospecting and account management.
The caller ID. The prospect sees whatever number the softphone presents. It must be a real business number, in the right country, that can be called back. A local area code can help recognition. US calls are also subject to STIR/SHAKEN attestation, and numbers that get flagged lose answer rates fast; our guide to a caller ID marked as spam covers diagnosis and fixes.
CRM logging. A call that does not appear on the contact record does not exist for the rest of the team. Check that every call syncs automatically with its date, duration, outcome and, ideally, its recording. Our article on phone system CRM integration goes into detail.
Recording and transcription. Useful for coaching and account memory, but consent rules apply, and several US states require all parties to agree. Our call recording notice generator writes the disclosure.
Dialing mode. A plain softphone dials one number at a time, by hand. Past a few dozen calls a day, a dialer recovers most of the dead time between calls: a power dialer works through a list automatically, and a parallel dialer dials several numbers at once.
Texting. A text after a missed call or to confirm a meeting rounds out the call, from the same number.
Mobility. Calls made from a smartphone between meetings should land in the same place as desk calls. That is the whole point of a mobile softphone app over a personal cell line.
The headset. It is the only hardware to buy, and it matters more than the computer. A wired USB headset with a noise-canceling mic avoids most of the echo and muffled audio that people wrongly blame on the software.
We compare the apps that cover these needs in our roundup of the best softphone apps for sales.
What internet connection do you need?
This is the most common question, and the answer surprises people: little bandwidth, but a steady connection.
A G.711 call uses roughly 100 kbps in each direction. Ten reps on the phone at the same time fit in 1 Mbps of upstream. What degrades a call is almost never bandwidth; it is these three numbers:
| Metric | Acceptable threshold | What you hear past it |
|---|---|---|
| One-way delay (latency) | under 150 ms (ITU-T G.114) | People talk over each other |
| Jitter | under 30 ms | Robotic voice, garbled syllables |
| Packet loss | under 1% | Choppy audio, missing words |
Those thresholds and the settings that hold them (voice prioritization on the router, cable rather than Wi-Fi for fixed seats) are covered in our guide to business VoIP phone service. To see where your own connection stands, our VoIP speed test measures these metrics from the browser.
What about 911 on a softphone?
This is the one topic US buyers cannot skip. A softphone is not tied to a street address the way a copper line was. The FCC rules implementing Kari’s Law and the RAY BAUM’S Act address this:
- Kari’s Law requires multi-line telephone systems to allow direct 911 dialing without a prefix and to notify a designated contact when 911 is called.
- RAY BAUM’S Act rules require a dispatchable location to be sent with 911 calls. For non-fixed devices such as softphones, that location must be provided automatically when technically feasible; otherwise the service can rely on a location the user registers or confirms, or on other approved location data.
In practice: ask your provider how 911 is routed from its softphone, what address is sent, and how remote employees update theirs. This is a compliance question for the phone service, not legal advice.
The limits of a softphone
A softphone has constraints a desk phone does not. Know them before you unplug every desk set.
- It depends on the device. Laptop asleep, battery dead, tab closed: the softphone stops ringing. For critical inbound calls, set up forwarding to a mobile or a device that stays on.
- It depends on the network. An internet outage drops the call in progress. The mobile app can take over on cellular data, provided it is installed and signed in.
- Mobile notifications. Smartphone operating systems restrict background activity to save battery. Make sure the app is allowed to ring when the screen is locked.
- Free softphones. A free SIP client is calling software, not a service. You must find a carrier, configure it yourself, and it brings no CRM sync, no reporting, no central recording. Some, such as Zoiper’s free edition, are also limited to non-commercial use according to the publisher.
Is Skipcall a softphone?
Yes. Skipcall runs in the browser and as an iOS and Android app, with no desk phone and nothing to install on the computer. Business numbers are included in 14 countries in the base offer (including the United States, Canada, the United Kingdom, France and Germany), and numbers in other countries can be opened on request through support. To keep an existing number, Skipcall handles porting for both landline and mobile numbers: the team manages the port with your current provider, on request through the chat; our number porting guide explains the process.
What Skipcall adds to a basic softphone: every call lands on the contact record and syncs to HubSpot, Pipedrive, Salesforce or Attio, with its transcript. Texts are sent and received from the same numbers. The Business VoIP plan starts at $25 per user per month billed annually. The prospecting plans, from $70 per license per month billed annually, add a power dialer, a parallel dialer with up to 4 lines, and, when a call reaches an answering machine, an automatic prerecorded voicemail or text. Details are on the pricing page.
What Skipcall does not do: no phone menu (IVR), no call queues, no inbound call routing. For a front desk that handles heavy inbound traffic and splits it between departments, a full business phone system is a better fit; our guide to business phone systems helps you choose.
What to remember
- A softphone is software that replaces the desk phone: a desktop app, a browser tab or a mobile app, used with a headset.
- It runs on voice over IP. In the browser, it relies on WebRTC, a W3C Recommendation since January 2021.
- It differs from an IP phone (a physical device) and from your mobile’s built-in phone app (which uses your carrier and your personal number).
- Bandwidth needs are small, around 100 kbps per call. Stability is what counts: delay under 150 ms, jitter under 30 ms, loss under 1%.
- In the US, ask how 911 location works for softphone users, especially remote staff.
- To sell, a softphone must come with a business number, CRM logging and, at volume, a dialer.
