VoIP, otherwise known as Voice over Internet Protocol, is a digital solution for telecommunication that utilizes the transmission of voice through the use of data over the internet. This technology is typically adopted for both commercial and privately used applications. VoIP developers specialize in programming telecommunication systems using data transmission to provide efficient services for audio and video functions.

VoIP developers are highly sought after professionals as they can create a versatile and advanced system for both desktop and mobile devices. This can include creating a more interactive experience for customers with multi-way calls, conference calls, video conferencing and voicemail systems. VoIP developers can set up your business’s phone system such as forwarding calls remotely to other devices with extensions or even communicating with customers utilizing software like Callcentric, Flowroute or Voxbone.

Here's some projects that our expert VoIP Developer made real:

  • Secured and configured private networks by implementing security measures like IP SLA, NAT and ACLs
  • Integrating SIP trunks between billing platforms, PBXs and VoIP applications
  • Setting up Postfix mail server on Linux systems with TLS authentication and encryption
  • Installing and configuring sip telephony software like ASTPP into businesses
  • Developing web applications that can send and receive SMS messages utilizing VoIP APIs

Our expert VoIP Developer have created numerous projects to help business owners manage their telecommunications in a professional bet. Our developer have an array of experience in creating a secure and reliable system customized to each client demands. If you're looking to improve or create your business’ communication system, then post your project today on Freelancer.com to hire one of our skilled professional VoIP Developers today!

From 24,523 reviews, clients rate our VoIP Developers 4.83 out of 5 stars.
Hire VoIP Developers

VoIP, otherwise known as Voice over Internet Protocol, is a digital solution for telecommunication that utilizes the transmission of voice through the use of data over the internet. This technology is typically adopted for both commercial and privately used applications. VoIP developers specialize in programming telecommunication systems using data transmission to provide efficient services for audio and video functions.

VoIP developers are highly sought after professionals as they can create a versatile and advanced system for both desktop and mobile devices. This can include creating a more interactive experience for customers with multi-way calls, conference calls, video conferencing and voicemail systems. VoIP developers can set up your business’s phone system such as forwarding calls remotely to other devices with extensions or even communicating with customers utilizing software like Callcentric, Flowroute or Voxbone.

Here's some projects that our expert VoIP Developer made real:

  • Secured and configured private networks by implementing security measures like IP SLA, NAT and ACLs
  • Integrating SIP trunks between billing platforms, PBXs and VoIP applications
  • Setting up Postfix mail server on Linux systems with TLS authentication and encryption
  • Installing and configuring sip telephony software like ASTPP into businesses
  • Developing web applications that can send and receive SMS messages utilizing VoIP APIs

Our expert VoIP Developer have created numerous projects to help business owners manage their telecommunications in a professional bet. Our developer have an array of experience in creating a secure and reliable system customized to each client demands. If you're looking to improve or create your business’ communication system, then post your project today on Freelancer.com to hire one of our skilled professional VoIP Developers today!

From 24,523 reviews, clients rate our VoIP Developers 4.83 out of 5 stars.
Hire VoIP Developers

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    14 jobs found

    My FreePBX server is already connected to a Twilio Elastic SIP Trunk using a Credential List. Zoiper extensions register without issue and the PJSIP endpoint for Twilio shows “Available,” yet every outbound attempt returns “All circuits are busy now.” Nothing at all appears inside the Twilio call logs, so the traffic never reaches their side. I suspect the PJSIP trunk settings are to blame, though the outbound route or some subtle SIP-signaling mismatch could also be involved. No recent changes have been made to the trunk configuration, so whatever is wrong has likely been there from the start. What I need from you • Trace and isolate the fault across the outbound route, PJSIP trunk, and SIP signaling (sngrep or tcpdump, Asterisk CLI, etc.). • Apply the ...

    $17 Average bid
    $17 Avg Bid
    6 bids

    I’m looking for a reliable specialist who can take charge of our phone line and give every caller a smooth, professional experience. Your main focus will be to resolve issues quickly so customers end each call feeling heard and helped. What you’ll do • Answer inbound calls during our business hours (we’ll provide a VoIP number). • Listen actively, identify the root of each problem, and deliver clear, concise solutions or next steps on the spot whenever possible. • Log every interaction in our CRM with call notes, follow-up actions, and resolution time. • Escalate only the cases that truly require higher-level intervention. What I’ll supply • A concise knowledge-base and onboarding guide. • Access to the CRM, call script templa...

    $337 Average bid
    $337 Avg Bid
    24 bids

    I am ready to launch a new voice service and need a fully verified USA-based SIP trunk that lets me place and receive both domestic and international calls. Monthly traffic will sit in the 1,000 – 10,000-minute range and the trunk must support several concurrent calls without choking, so adequate channel capacity is essential. Here is what I need from you: • Introduce or provision a reputable provider that can activate an account in my company’s name with all necessary KYC completed. • Ensure the trunk is enabled for two-way voice, CLI presentation, 911 compliance, and international reach. • Supply full connection details (SIP URI, username/password or IP auth, codec list) plus concise step-by-step setup instructions for popular soft-switches or an Aster...

    $53 Average bid
    $53 Avg Bid
    3 bids

    Configure HG8120C XPON ONU to use LAN 1 as WAN port instead of GPON, to access Internet & VoIP Server on LAN port 2 in Routing mode bet Port1 & Port 2.

    $20 Average bid
    $20 Avg Bid
    5 bids

    Senior Real-Time Audio Software Engineer Needed We are looking for an experienced Senior C# Audio Software Engineer to develop a professional Offline Interpreter Console Software for conferences and simultaneous interpretation. This is NOT a standard desktop application. The project requires proven experience in: Real-Time Audio Processing Ultra-Low Latency Networking C# WPF NAudio ASIO WASAPI UDP Audio Streaming Multi-threading Windows Desktop Development Project Overview The application will run entirely on a local Gigabit Ethernet network with no internet dependency. Main features include: Ultra-low latency audio (<20ms) Professional audio routing Multi-channel output Strict channel isolation Supervisor Dashboard Local recording LAN messaging Automatic device discovery Hardware compa...

    $46 / hr Average bid
    $46 / hr Avg Bid
    61 bids

    Design, configure, and maintain Asterisk-based telephony systems. Develop and manage SIP trunk configurations, IVRs, call routing, DID management, and dial plans. Integrate telephony systems with REST APIs, webhooks, and third-party platforms. Build and maintain API integrations for the Neurova platform. Configure inbound and outbound call flows, click-to-call, predictive dialing, and intelligent routing. Work with AI Voice Agents and ensure seamless human call transfer (human failover). Integrate WhatsApp, SMS, Email, CRM, and other communication channels where required. Troubleshoot voice quality, SIP signaling, RTP issues, and carrier connectivity. Collaborate with the AI development team to integrate Speech-to-Text (STT), Text-to-Speech (TTS), and LLM-based conversational workflows. Op...

    $173 Average bid
    $173 Avg Bid
    35 bids

    I already have a Grandstream UCM-series IP PBX on site and reachable for remote work. The hardware is up, the , but the system is still running on factory defaults. I need a Grandstream-savvy engineer to jump in and complete the core setup: • Create and test all user extensions (SIP and any analog FXS ports that may be required). • Build a clean inbound route so external calls land where they should. • Design and activate a simple operator/IVR menu that greets callers, routes them to the right extension or ring group, and falls back to voicemail if unanswered. Please handle dial plans, basic voice prompts, time conditions, and any minor tweaks that are typically part of making the above work smoothly. I’ll supply extension lists, Remote access is available via Te...

    $38 Average bid
    $38 Avg Bid
    23 bids

    I’m building a small customer-care desk for a telecommunications service and I need a warm, friendly FEMALE voice that sounds naturally North-American—think clear United States accent, with the flexibility to soften into Canadian when a caller’s location makes that helpful. Your role will be to pick up inbound calls and return the occasional voicemail, resolve everyday service inquiries, and keep the experience smooth from “hello” to “good-bye.” Because our product is telecom, previous experience talking customers through network, SIM, or billing questions will let you succeed from day one. We work entirely online, so you’ll log each interaction in our CRM, jump on VoIP through your own reliable headset and broadband connection, and esc...

    $29 Average bid
    $29 Avg Bid
    9 bids

    I need an Android application that lets users talk to each other in real time. The experience should feel as close to a normal phone call as possible, with rock-solid, low-latency audio that holds up even on average mobile connections. One crucial requirement is support for group calls; several participants must be able to join the same room, speak freely, and hear one another without noticeable lag or echo. If you have already built something similar—or, as I mentioned, completed a “brikri” project before—please let me know, because proven experience with live voice stacks will save both of us time. Whether you prefer WebRTC, Agora, Twilio Voice, Jitsi, or another VOIP backbone, I am open to whichever engine delivers the most stable performance on Android. Just bu...

    $1737 Average bid
    $1737 Avg Bid
    238 bids

    I’m running a 3CX Professional installation where voicemails have suddenly stopped being stored on the server and are no longer reaching users’ mailboxes. The PBX hasn’t been updated recently, so this isn’t tied to a new build or hot-fix. What I’ve already covered: I verified the voicemail settings, restarted the whole system, and combed through the logs, yet I still can’t see any obvious misconfiguration or error that explains why messages vanish. Here’s what I need from you: • Pinpoint the exact cause of the voicemail failure (storage path, permissions, SMTP issues, service crashes—whatever the root happens to be). • Apply or walk me through the fix during a remote session so that new voicemails are both retained on the PBX ...

    $22 / hr Average bid
    $22 / hr Avg Bid
    35 bids

    I'm looking for a VOIP system to automate customer interactions for my micro-company selling CBD food supplements and cosmetics. The system should: - Answer customer inquiries - Process orders - Provide product recommendations Communication methods: - Voice calls - Email Response type: AI-generated responses Ideal skills and experience: - Experience with VOIP systems - Familiarity with AI response generation - Background in e-commerce, especially in the CBD or supplement industry I prefer Claude AI

    $649 Average bid
    $649 Avg Bid
    126 bids

    I’m organising an intensive VMware Cloud Foundation (VCF) programme for an advanced technical audience and would like an experienced instructor to run the sessions live online for a group of about 11-20 engineers. What I need from you • A concise trainer profile highlighting VCF implementation or architecture projects you have led, past teaching engagements, certifications, and any customer references you can share. • A full course outline following the order below, showing sub-topics, lab time and estimated hours per section: – VCF Architecture Deep Dive – Deploying VMware Cloud Foundation – VCF Management Domains and Workload Domains – Lifecycle and Automation – Aria Suite (Automation & Operations) – Monitori...

    $53 / hr Average bid
    $53 / hr Avg Bid
    6 bids

    SMS SPECIALIST MUST HAVE OWN SMS PLATFORM 2 PART PROJECT YOU CAN DO ONE OR BOTH 1. Set up and execute a trickle text broadcast to the U.S. 50 texts an hour for 12 hours a day until list of 2000 to 3000 is completed..... probably you will use a local text broadcaster in your country 2. Locate or Create a desktop application or software that will send a trickle text campaign via Android or Voip SEVERAL SUGGESTED APPS ARE MYSMS MIGHTYTEXT GOOGLE MESSAGES That will send 50 texts an hour until list of 2000 to 3000 is completed We will pay a premium for one or both of above Do not solicit HI-LEVEL or A2P services

    $144 / hr Average bid
    $144 / hr Avg Bid
    30 bids

    Buscamos Ingeniero de Telecomunicaciones / Administrador de Sistemas Senior con experiencia avanzada en VICIdial y Asterisk PBX (Habla Hispana). Responsabilidades y tareas clave: Optimización de infraestructura: Configuración, mantenimiento y tuning de servidores VICIdial (arquitectura Single o Cluster). Bases de datos: Optimización fina de base de datos (MySQL / MariaDB) para soportar alto volumen de llamadas simultáneas y evitar bloqueos de tablas. Desarrollo e IVR: Configuración de campañas predictivas, gestión de IVR avanzado, enrutamiento inteligente y scripts AGI personalizados. Soporte y conectividad: Resolución de problemas de latencia, calidad de audio y configuración de troncales SIP / carriers. Requisitos indis...

    $48 / hr Average bid
    NDA
    $48 / hr Avg Bid
    32 bids

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