ZoiPer Pro - SIP Softphone

Review by eFreeware

Most VoIP apps on Android are tied to one service. ZoiPer Pro is the opposite: a standalone softphone that speaks SIP and IAX, the two signaling protocols used by a large share of business phone systems, and connects to whichever provider or PBX you already pay for. That independence is the whole point of the app, and it is why it turns up in call centers, small offices and home setups where the phone service and the phone app are separate decisions.

It costs $9.49 up front, carries no advertising, and the developer also offers in-app purchases. With more than 10,000 installs and a 4.1 average across 1,806 ratings, it has a long track record behind it, having first appeared in November 2016. The people I would expect to get value from it are those who already have a SIP or IAX account, or who administer one, and who want a client they can tune rather than a consumer calling app.

The developer also runs a public beta channel for Pro users, and the notes for it mention a new interface, multiple and custom color themes, better Bluetooth support, a reworked approach to network changes and a new notification system. Those are the areas the team appears to be working on next.

Protocol support is the selling point

The core of the app is multiprotocol calling. It handles SIP and IAX, and the developer describes it as compatible with RFC-compliant PBXs, which is the practical detail that matters if you are pointing it at an office phone system rather than a consumer service. Calls run over either WiFi or 3G, so a handset can stay reachable on a mobile network when it is away from the office.

Audio is handled by a set of codecs that includes g711 in both ulaw and alaw variants, speex, iLBC and gsm, with wideband audio also supported. Between them these cover the narrowband standards most PBXs expect and the compressed options you would choose on a thin connection. Built-in echo cancellation and STUN support round out the parts of a call path that usually cause trouble on mobile.

Security is covered by ZRTP and TLS, and DNS SRV lets the app discover a provider's servers from a domain name instead of making you type in addresses by hand. If your provider publishes SRV records, setup becomes considerably shorter.

Everyday calling tools

Around the call itself, ZoiPer Pro covers the controls a desk phone would give you: mute, hold, speakerphone, call waiting and call transfer, plus DTMF sending for navigating automated menus. You can set a different ringtone for each account, which is useful when one handset carries both a work line and a personal one.

The app integrates with the native Android contact list, so names and numbers you already have show up rather than living in a separate address book. Video support is included as well. Background and multitasking support means a call can continue while you use other apps, which is the behavior most people expect from a phone and not something every softphone manages.

Two transport options are offered, UDP and TCP. The developer's own advice is to use TCP for better battery life, a small configuration choice worth remembering if you keep the app registered all day. Bluetooth support is still in beta, so headset behavior is one area that is not yet settled.

What you need before it works

This is the part worth reading twice. ZoiPer Pro is client software only; it does not include any calling service. To place or receive calls you need a subscription with a SIP or IAX provider, or access to a PBX, and that is a separate cost from the $9.49 you pay for the app. There is no way around this, and anyone expecting an app that simply makes cheap calls out of the box will be disappointed.

There is also a licensing wrinkle to understand before buying. In-app purchases made in the free version do not carry over to Premium, and purchases made in Premium do not carry over to the free version; the two are separate. The developer notes that Premium contains the advanced features found in Zoiper Gold, and that anyone who already bought Gold has those features already. If you are moving between versions, that is worth checking before you spend anything.

For organizations, the developer offers a free automatic provisioning system through its OEM portal, which is intended to save configuring handsets one at a time. Whitelabel versions and a VoIP SDK are available on request for anyone building a product around the client.

Using it sensibly

Emergency calling is the most important point to understand before relying on the app. Using ZoiPer as your default dialer may interfere with reaching 911, so it makes sense to treat it as a second line on a phone that still has a normal cellular dialer, rather than as the only way to make a call. That is a sensible precaution for any VoIP client, and here the developer states it plainly.

There is a compatibility note too: certain Alcatel One Touch models and the HTC One M8 are called out as unstable, with the developer pointing to broken audio implementations on those handsets that can cause freezes and crashes. If you are planning to deploy the app across a fleet of older phones, checking the list first is cheaper than finding out afterward.

The developer also warns that unofficial copies of the app circulating as APK files may contain a trojan capable of capturing credentials and placing fraudulent calls, and asks users to install only from the app store. On a softphone, where an account can be used to dial premium numbers, that warning deserves attention.

One more practical note: the developer points users to a community forum for support, so the ability to search and describe a problem clearly will serve you well if something goes wrong.

The trade-offs to weigh

The price is the first thing to consider. At $9.49 with in-app purchases on top, this is not an impulse install, and it only makes sense if you have a SIP or IAX account to point it at. Someone without a provider has nothing to plug it into, however good the client is.

Bluetooth is still in beta, and the beta channel covers reworked interface, themes, network handling and notifications, so those areas are still in motion.

The 911 warning and the list of unstable handsets are the kind of caveats that matter more here than in most apps, because a softphone may be someone's working line. Neither is unusual for VoIP, but both should shape how you deploy it.

A softphone for people who already have a provider

ZoiPer Pro is a well-specified SIP and IAX client with the codecs, transports and encryption options that business telephony expects, sold at a flat price with no advertising. It has been on the store since 2016 and is still being updated, with the most recent release bringing edge-to-edge layout work, an optional SIP Preconditions setting for accounts, and crash fixes.

It suits two groups in particular: individuals who already pay for a SIP or IAX service and want a configurable client for it, and administrators who need to put a softphone on a set of handsets, where the OEM provisioning system and the option of a whitelabel build become relevant.

For everyone else, the combination of protocol support, call controls and a one-time price is a reasonable proposition, provided you read the compatibility and emergency-calling notes first.

What's new in version 2.26.13

v2.26.13 Edge to Edge improvements Add "SIP Preconditions" for accounts(disabled by default) Crash fixes