Mobile appMessaging & callsOriginal by Rakuten Viber
Viber is one of the apps that popularised the idea of free calls over the internet, and today it offers messaging, communities and business communication together. The ability to call a landline or mobile of someone who does not use the app at a low rate is valuable, especially for people with relatives abroad. Stickers and large communities keep users in the app.
Building something similar takes encrypted messaging and VoIP calling infrastructure, plus a SIP/telecom gateway that passes calls to regular phone networks and a per-minute billing system. Communities and channels, a sticker store, business messages and chatbots, a credit purchase flow and an admin panel are the other parts of the product. Interconnection agreements with telecom operators and local regulations also need to be reviewed.
How Viber works: the core user flow
How many apps and dashboards do you need?
Mobile app
The end-user app for messaging, free calls, paid calls to phone networks and communities.
Desktop client
The client that pairs with the phone for messaging and calling from a computer.
Business panel
The panel where brands send notifications and campaigns from a verified account and set up chatbots.
Admin and billing panel
The panel that manages per-minute rates, credit sales, carrier costs and fraud detection.
Critical features of a product like Viber
Calls out to phone networks
Landline and mobile numbers around the world are called with in-app credit through a SIP gateway.
Per-minute billing
Rates that vary by country and carrier are managed with real-time credit deduction and call records.
Communities
Community chats with many members, admin roles and pinned messages can be created.
Sticker store
Free and paid sticker packs are downloaded, and brands can publish sponsored stickers.
Business messages
Order, shipping and verification notifications are delivered from approved business accounts.
Disappearing and hidden chats
Messages are deleted after a set time, and the other party is warned when a screenshot is taken.
What goes into the first version, what comes later
First version (MVP)
- One-to-one and group messaging
- Free voice and video calls
- Sticker packs
- Community chats
- Push notifications and media sharing
Later releases
- Paid calls to phone networks and credit
- Business messages and chatbots
- Desktop client
- Paid sticker store
Modules and how the budget is calculated
The budget is calculated with 360 SOFT’s pricing model from the modules below, about 32 screens and the project’s complexity: roughly 208 person-days for the full scope and 136 person-days for the first version. Every module you drop lowers the budget directly.
| Module | Phase |
|---|---|
| Sign-up, login, social login | First version |
| User profile and settings | First version |
| Roles and permissions | First version |
| Admin dashboard | First version |
| Real-time messaging | First version |
| Push notifications | First version |
| File, photo, video upload | First version |
| Video / voice calls | First version |
| Online payments (Stripe / PSP) | First version |
| GDPR and security hardening | First version |
| Reporting and analytics | Later release |
| Third-party API integration | First version |
| Multi-language | First version |
Hosting, SMS, map APIs, app store accounts and payment-provider fees are separate items. Maintenance and improvements (optional): €700 / month. We send a fixed written price within 24 hours after a free discovery call.
The hard parts
Telecom integration
Calling phone networks requires agreements with wholesale voice carriers, caller ID handling and quality management.
Call fraud
Credit bought with stolen cards and fake calls to premium-rate numbers cause serious losses.
Voice quality
Cross-country latency and packet loss degrade audio, so distributed media servers and adaptive codecs are a must.
Business model
The main revenue lines are credit for calls to phone networks and monthly minute bundles, paid sticker packs and a per-message fee charged to businesses. Ads shown in community and chat lists add further income. For credit sales, in-app purchase rules and licensed payment infrastructure must be used.
Get a free quote for your project
Let us scope it together and send a fixed written quote within 24 hours. NDA on request; you own the source code.
Choosing a company to build an app like Viber
Most people searching “build an app like viber” are really looking for a reliable app development company. When comparing quotes, check four things:
- Can you try similar products they have shipped, in the stores or live?
- Are the source code, design files, servers and store accounts transferred to you by contract?
- Do they show a working demo every two weeks, with written scope and acceptance criteria?
- Are maintenance, scaling and GDPR/security costs written into the quote?
Copyright and trademarks
A business model and features are generally not protected on their own, but the Viber name, logo, interface design, content and source code are. That is why we build a product with similar functionality but your own brand, design and code. This is not legal advice; we recommend a trademark search before launch.
Frequently asked questions
How long does it take to build an app like Viber?
A first version with messaging and in-app calling takes a few months. Outbound calling to phone networks should be planned as a separate project because of carrier agreements.
Do I need permission to call regular phones?
Terminating calls to phone networks is subject to telecom regulations that vary from country to country, and a licence from the local telecom regulator may be required. Working with licensed voice carriers makes the process easier.
Will there be copyright or trademark issues?
The messaging and calling business model is generally free to use, but the name, logo, design, stickers and code cannot be copied. This is general information, not legal advice.
What should I look for when choosing a company to build a calling app?
Choose a team with VoIP, SIP and WebRTC experience that can test voice quality on different networks and has built billing systems.
