Voice & VoIP
Audio calling & VoIP app development with crystal-clear voice
Finashtech builds audio calling apps, VoIP software and in-app voice calling — one-to-one and group calls that sound clear on weak networks, ring like a native call on mobile, and can connect to ordinary phone numbers when you need them to.
Audio meetings with recordings and transcripts are already part of TeamCollab, our own collaboration platform, so we bring hands-on experience of the details that make voice feel effortless.
Voice calling features we build
From a simple call button inside your app to a full VoIP product, we build the parts users notice — and the parts they never should.
One-to-one & group voice calls
Reliable audio calls between users, or group audio rooms for teams and communities.
In-app voice calling
Let customers call support, an advisor or another user directly inside your app, without exposing personal phone numbers.
Native ringing on iOS & Android
Incoming calls that ring on the lock screen using CallKit and Android's telecom APIs, with push notifications that wake the app.
Recording & transcription
Optional call recording with automatic transcripts and consent prompts — searchable later, like TeamCollab meetings.
Call history, presence & routing
Online status, missed-call handling, call queues and routing rules for support and sales teams.
Phone network bridging
Connect app calls to regular phone numbers through SIP trunks from licensed telephony providers.
VoIP architecture that sounds clear
Good voice quality is engineering, not luck. We tune the full path from microphone to speaker.
Opus codec & adaptive bitrate
Wide-band audio that adapts to the connection, staying intelligible even on congested mobile data.
Echo cancellation & noise suppression
Acoustic echo cancellation, noise suppression and automatic gain control for calls from noisy, real-world places.
Jitter buffers & packet-loss concealment
Smooths out network hiccups so short drops do not become robotic or broken audio.
WebRTC, SIP or both
WebRTC for app-to-app calls, SIP for telephony integration, and gateways between them when your product needs both worlds.
Voice call SDK integration — or your own stack
Sometimes the fastest route is a proven voice SDK or communications platform; sometimes owning the stack is cheaper at scale. We help you choose, then build it properly.
SDK & CPaaS integration
Integrate a third-party voice call SDK into your app with your own UI, authentication and analytics — and an abstraction layer that avoids lock-in.
Self-hosted VoIP
Open-source media and signalling servers on your own cloud for full control over cost, data and features.
Secure by default
Encrypted media (DTLS-SRTP / SRTP), authenticated signalling and fine-grained access to recordings — fintech-grade discipline.
Where audio calling makes the difference
Voice is often the most human channel a product can offer — and the one users expect to just work.
Customer support lines
Click-to-call from your app or website, routed to the right agent with the customer's context on screen.
Fintech advisory & collections calls
Recorded, auditable calls between customers and advisors, connected to the account they concern.
Telehealth audio consultations
Voice-only consultations for patients on low bandwidth, with appointment and consent flows.
Field teams & communities
Push-to-talk style coordination for distributed teams, and group audio rooms for communities.
Proof, not promises
Proof in our own product: TeamCollab
TeamCollab includes voice-only and video meetings for teams and their clients, with recordings and auto-generated transcripts. We build and run it ourselves — the same engineering standards apply to the VoIP and audio calling apps we build for you.
See how TeamCollab worksTechnology
Typical technology stack
Chosen per project, based on your platforms, call volumes and telephony needs.
Voice & signalling
- WebRTC
- SIP
- Opus codec
- STUN / TURN
Mobile
- CallKit (iOS)
- Android telecom APIs
- Push notifications
- React Native
Backend
- Node.js
- WebSockets
- Call routing & queues
- Recording pipeline
Cloud
- Docker
- Auto-scaling media servers
- Encrypted storage
- Monitoring
Process
How we deliver your project
Discovery & call-flow design
We map who calls whom, on which devices, how often and with what privacy needs — then agree on scope, platforms and a milestone plan.
Architecture & first working call
We pick the right topology (peer-to-peer, SFU or a managed SDK) and get a real call running early, so decisions are tested, not guessed.
Build & test on real networks
Features are built in sprints and tested on weak Wi-Fi, mobile data and strict firewalls — the conditions your users actually have.
Launch, monitor & scale
We deploy, watch call-quality metrics and capacity, and stay on to support and extend the product after go-live.
FAQ
Frequently asked questions
What is the difference between VoIP and regular phone calls?
VoIP (Voice over IP) sends calls over the internet instead of the traditional phone network. That makes in-app calling, recording, transcripts and integration with your product possible — and it can still connect to normal phone numbers through SIP when needed.
Can our app call real phone numbers?
Yes. We bridge app calls to the public phone network using SIP trunks from licensed telephony providers, so users can call landlines and mobiles or receive calls on a business number.
Do you build with a voice call SDK or from scratch?
Either. A voice call SDK gets you to market quickly; a self-hosted VoIP stack lowers running costs at scale and keeps data on your infrastructure. We recommend an approach after understanding your volumes and timeline.
Will calls work on poor mobile networks?
We design for it: the Opus codec, adaptive bitrate, jitter buffers, packet-loss concealment and TURN relays all help calls stay clear on congested or restricted networks. We also test on real weak connections before launch.
Can incoming calls ring like a normal phone call on iOS and Android?
Yes — using CallKit on iOS and Android's telecom APIs with push notifications, incoming VoIP calls appear on the lock screen like a regular call.
Can calls be recorded for compliance?
Yes. We add consent prompts, secure encrypted storage, retention rules and audit logs, so recorded calls meet the policies your business has to follow.
Start a project
Adding voice to your product?
Tell us how your users need to talk. We will reply within one business day with a recommended approach and next steps.