InstaVoIP for the iPhone was created using the InstaVoIP Mobile SDK, an optimized Voice-over-IP (VoIP) solution for Apple iOS from Unicoi Systems.

Our team is comprised of hardware and software engineers with over 100 years of collective experience. All of our engineering work is done by Unicoi Systems engineers, located in the United States.

InstaVoIP for the iPhone is a standalone softphone that requires a SIP server or subscription with a SIP-based VoIP provider to make calls.

InstaVoIP features include:
- WiFi and data connection compatible softphone with excellent voice quality over both.
- Multi-tasking support, enabling users to background InstaVoIP and still receive incoming calls while performing other tasks.
- Direct interface into your existing address book to easily add, remove, or edit existing contacts.
- Favorites list for easy one-touch dialing of frequently used numbers.
- Speakerphone, mute, hold, and DTMF capabilities.
- Swap between, conference, split, and transfer two separate calls.
- Call History with detailed information for received, missed, and outgoing calls.
- STUN for network traversal
- Noise reduction, acoustic echo cancellation, and VAD for better media quality and efficiency.
- Quality of Service

Audio Codecs Supported:
- G.711 uLaw/aLaw
- G.722 HD
- G.726 (16/24/40kbps and fixed payload)
- DV14 (HD and Narrowband)
- Linear PCM (normal and HD in addition to Little Endian support for both)
- iLBC
- SPEEX (Narrowband and Wideband)
- SILK (Narrowband and Wideband)

While InstaVoIP for iPhone will work over 3G with correct Transport and STUN settings, some mobile network operators may restrict VoIP functionality over their network or charge additional fees. Unicoi Systems, Inc. is not liable for any charges, fees, or liability imposed by your carrier for use of VoIP over 3G.

What’s New

Version 2.0.0

- Now supports iOS 10 fully
- Removed Contacts and Favorites for now. They will return in the future!
- Entirely new UI engine running beneath for improved stability!
- Bug fixes


Unicoi Systems, Inc.
10.2 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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