Top 10 Custom AI Voice Agent Development Companies [2025]
A carefully hand-picked list of the best companies that offer AI Voice Agent Development Services
If you are planning to add an AI voice agent into your business, you need to find the one best voice AI development company that perfectly fits your requirements, budget and infrastructure.
How to find the one?
We’ve put together a list of the most hired AI voice agent development companies. Check out their services, capabilities and pricing to find out which provider aligns best with your business goals.
Table of Contents
What Is An AI Voice Agent?
An AI voice agent is a software that uses artificial intelligence to understand the intent of a conversation and respond in a human-like voice and tone.
These software help automate conversations on a platform using technologies like automatic speech recognition (ASR), natural language processing (NLP), and text-to-speech (TTS).
Businesses use these agents to build virtual assistants, customer service agents and outbound calling tools that make everyday operations easier and smoother.
What Are The Key Features To Look For In An AI Voice Agent Development Service?
When you choose an AI agent provider, you must ensure that they are capable of developing the below mentioned core voice ai ahet features. You may include more, but make sure you choose a partner that does not skip any of these features.
- Real-time Automatic Speech Recognition (ASR): This feature converts the users’s speech input into text instantly.
- Text-to-Speech (TTS) with Natural Prosody: Supports the voicebot to generate replies in humanized voice.
- Low Latency Response Handling: This feature is necessary for delivering near-instant replies without delays.
- Barge-In Support: Detects when a user interrupts the voicebot’s response and adapts the response accordingly.
- Whisper / Agent Assist Mode: Makes your voicebots provide live suggestions and recommendations to human agents.
- Contextual Memory: Keeps a record of the conversation and provides answers based on this memory and past interactions.
- Dialog Management: Helps the voice assistants handle any kind of branching conversations and fallback flows.
- Multi-language & Accent Adaptability: Lets your voice assistants speak in any language or accent.
- Emotion & Sentiment Detection: Identifies tone of voice so the bot can adapt accordingly and provide responses.
- Voice Biometrics (optional in some): Lets your agents identify the person speaking to the bot and authenticate for further conversations.
- Custom Wake Word & Hotword Detection: Triggers agent activation when a particular word is spoken.
- Noise Suppression & Echo Cancellation: Improves clarity in real-world environments by cancelling out noise and echoes.
- Speech-to-Speech Translation (advanced providers): Lets you convert an ongoing speech into a different language.
- LLM Integration: Combines speech technology with large language models for reasoning.
Top 10 AI Voice Agent Development Services
Here is a carefully curated list of the best AI voice firms that can help you design, build and deploy your own voice assistants.
Why trust this list?
- We hand-picked this list after 13+ days of research and analysis
- Narrowed down after analysing 27+ providers, their offerings and pricing
- Prioritized features, security, development capabilities, technologies and 7 other core criteria.
We believe this makes the following list a reliable one before you decide upon which one to choose for your project.
Here’s the first best company:
1. MirrorFly
Best for: Businesses looking for Custom Communication Solutions
MirrorFly, originally launched as CONTUS Fly in 2025, is an Indian-US CPaaS platform owned by the prestigious CONTUS Tech.
The solution offers white-label AI voice agent SDK along with 15+ AI-powered SDKs including real-time video, voice and chat for website and mobile apps.
The company is highly preferred by enterprise businesses for its flexibility in offering both fully self-managed (on-premises) deployments and a cloud-based SaaS model (the Twin Model introduced in 2022)
When it comes to the data privacy of the AI voice assistants, MirrorFly stands out from other providers in the market with its custom security.
You can add N number of encryptions on top of MirrorFly’s default AES encryptions and SSL.
Ultimately, the solution also supports region-specific compliances on top of its GDPR, HIPAA and OWASP compatibility.
Another key highlight is the full control of data it offers. You build your AI voice agents with MirrorFly, but the company will not have any kind of access or control over your data.
This means, you get the source code, customize it as much as your business needs and deploy anywhere you prefer.
MirrorFly supports ultra-low latency as low as 3ms for voice calls, and has been recognized on industry sites (e.g. Softwaresuggest, FinanceOnline) as a leading chat/AI voice agent API provider, which assures that AI voice assistant built with this solution will respond to user queries without any delay.
It has a global footprint (with customers and developers in 25+ countries) and notable enterprise users across finance, healthcare, logistics and education sectors
In recent years MirrorFly has won awards for its user experience and reliability, and continues to expand its cloud platform while supporting self-hosted solutions for clients that require full control.
What are the key AI Agent Development services offered by MirrorFly?
- Custom AI Voice Agent Development
- Self-Hostable Voice Agent Platform
- Real-Time Conversation Intelligence
- Human Escalation / Handoff
| MirrorFly – Company & Services Profile | |
| Years in Business | 17+ years, founded in 2008 |
| Core Expertise | CPaaS for in-app messaging & voice/video + Custom Conversational AI Agents |
| Tech Stack |
|
| Deployment | Cloud SaaS, on-premise, supports self-hosting |
| Integration | 1000+ integrations (e.g. 3rd-party CRMs, SDKs) |
| Security | Custom security encryptions, AES, SSL, HIPAA, GDPR, OWASP |
| Industries Served | Healthcare, Education, Finance, E-commerce, Telecom or any industry |
| Primary Locations | USA, UAE & India (Global) |
How much does MirrorFly charge for AI Voice Agent development?
- Basic: $0.08/user/month
- Premium: $0.20/user/month
What are customers saying about MirrorFly’s AI Voice Agent Development service?
Overall, MirrorFly is an unavoidable choice for businesses that look for full-on customization, complete data control and white-labeling options for building their own voice agents.
2. VoiceSpin
Best for: Businesses that need to automate their Contact Centers
VoiceSpin, popularly known for its contact center solution is an Israel-based company founded around 2004-2005. While it started as a simple support platform, it slowly expanded its services and evolved into a powerful global communication platform provider.
Customers around the world find this AI voice company reliable for its own drag-and-drop IVR builder and AI scripts that has been a game-changer for several sales and support workflows.
As of this year, several sources claim that VoiceSpin continues to invest in voice AI features and integrations in order to maintain its market leadership in Israeli and global CCaaS markets.
What are the key AI Agent Development services offered by VoiceSpin?
- Omnichannel Voice Agent Automation
- Outbound AI Dialer & Predictive Calling
- Speech Analytics & Compliance Monitoring
| VoiceSpin – Company & Services Profile | |
| Years in Business | 19+ years (call-center solutions) |
| Core Expertise |
AI-powered contact-center platform Omnichannel voice bots |
| Tech Stack |
|
| Deployment | Cloud (SaaS) |
| Integration | 80+ CRM integrations |
| Security | GDPR |
| Industries Served | Retail, Hospitality, Sales & Support |
| Primary Locations | Italy/UK (Global) |
How much does VoiceSpin charge for AI Voice Agent development?
- Basic: $300/month
- Advanced: $525/month
- Enterprise: $1000/month
3. Apphitect
Best for: Organizations that look for Secure On-Premise Voice Solutions
Apphitect is a Dubai-based AI voice agent development firm (founded in 2008) known for offering Self-hosted communications APIs.
This white label voice AI agent provider is one of the pioneers in building easily-integratable and custom APIs and SDKs, helping businesses build their own voice assistants without any limitations on customization.
The company has a solid reputation in the UAE as a “leading mobile app development company” that also provides AI-powered communication solutions in recent years.
Apphitect’s AI voice agents stand out from the crowd with its 100% customizability & self-hosting solutions. You can deploy and manage their voicebots on your own servers and personalize any features, as you prefer.
Overall, Apphitect is a reliable AI Voice Agent Development company that helps your launch bots on-prem or cloud via their own flexible, developer-friendly solution.
What are the key AI Agent Development services offered by Apphitect?
- White-Label Voice Agent Development
- On-Prem SDK Deployment Services
| Apphitect – Company & Services Profile | |
| Years in Business | 17+ years |
| Core Expertise |
White-label AI Voice Agents Self-hosted CPaaS APIs & SDKs |
| Tech Stack | LLM, NLP, React Native, React, JS, Android, iOS & more |
| Deployment |
Private cloud On-premise |
| Integration | Supports 100+ third-party integrations |
| Security |
|
| Industries Served | Government, Telecom, Healthcare, Finance, Superapps |
| Primary Locations | UAE (Dubai) |
How much does Apphitect charge for AI Voice Agent development?
Apphitect offers its AI Voice agent services for businesses at a one-time license cost and it completely depends on the custom requirements of the business.
4. Retell
Best for: Brands that look for No-Code AI Voice Agent Development
Retell AI is a popular Silicon Valley startup that offers a no-code platform to businesses for building their own AI phone agents.
The company’s mission revolves around redefining business communications by automating outbound and inbound calls with natural-sounding AI agents
Retell is also known for an intuitive drag-and-drop builder that syncs with customers’ knowledge bases and tools like Cal.com, and for fully compliant operations.
What are the key AI Agent Development services offered by Retell?
- No-Code Voice Agent Builder
- Warm Transfer Agents
- Batch Calling & Campaign Agents
- Branded Caller ID Voice Agents
| Retell – Company & Services Profile | |
| Years in Business | Almost 3 years |
| Core Expertise | No-code builder for AI call agents Appointment & lead bots |
| Tech Stack | API + ML/NLP backend |
| Deployment | Cloud (SaaS) |
| Integration | SLLM integrations Webhooks |
| Security | SOC, HIPAA, GDPR |
| Industries Served | Healthcare, Insurance, Finance, Logistics, Home Services |
| Primary Locations | USA |
How much does Retell charge for AI Voice Agent development?
Retell charges its AI voice agent building service based on the call minutes. The cost revolves around $0.07 for every minute.
5. Synthflow
Best for: Teams that need AI Voice Agents with Enterprise Contact Centers
Synthflow is a European startup that specializes in building enterprise-grade voice AI agents.
When its co-founders initially developed this company, they planned it as a no-code platform. Businesses can use it to create AI phone agents for support, sales, and feedback calls, customizing them via visual workflows and prompts.
This helped several customers build agents without heavyload or complex processes, making the company a reliable option for AI voice agent development.
What are the key AI Agent Development services offered by Synthflow?
- LLM-Driven Voice Agent Construction
- Prebuilt Agent Templates
- Multilingual Voice Agent Deployment
| Synthflow – Company & Services Profile | |
| Years in Business | 2 years |
| Core Expertise | Enterprise voice AI OS |
| Tech Stack | No-code voice AI platform |
| Deployment | Cloud (SaaS) |
| Integration | 200+ |
| Security | Industry compliance |
| Industries Served | Contact Centers, BPO, Healthcare, Finance |
| Primary Locations | Germany |
How much does Synthflow charge for AI Voice Agent development?
Synthflow charges for its AI agent development based on 4 common packages:
- Starter: $29/month
- Pro: $450/month
- Growth: $900/month
- Agency: $1400/month
6. Vapi
Best for: Businesses that look for Developer-Centric Voice AI
Vapi is a San Francisco-based AI Voice Agent Development Agency founded 2023. This company is well-known for its developer-first platform that supports businesses to deploy their own AI voice agents.
Vapi has customers across sectors like finance, healthcare, travel, and home services with popular brands as clients including Mindtickle and Luma Health.
As a top voice AI company, Vapi claims to handle millions of calls by combining conversational AI with existing IVR infrastructure.
What are the key AI Agent Development services offered by Vapi?
- API-First Voice Agent Platform
- Custom Prompt-Based Agent Builder
- Demo Use-Case Agents
| Vapi – Company & Services Profile | |
| Years in Business | 5 years |
| Core Expertise | AI Voice API |
| Tech Stack |
API/SDK for voice applications Custom LLMs |
| Deployment | Cloud (SaaS) |
| Integration | 40+ |
| Security | Platform security |
| Industries Served | Startups to Fortune 500 |
| Primary Locations | USA |
How much does Vapi charge for AI Voice Agent development?
Vapi charges a flat rate of $0.05/min as platform fee along with charges for telephony & LLM
7. Cognigy
Best for: Companies that aim for Enterprise Automation
Cognigy is a well-established voice AI agent development agency headquartered in Düsseldorf with a US HQ in Dallas, Cognigy was started in 2016 by two ex-SAP engineers to automate customer service operations using AI-driven voice and custom chatbots.
Its flagship product, Cognigy.AI, is an omnichannel platform that can manage voice IVRs, web chat, and messaging in 100+ languages.
What are the key AI Voice Agent Development services offered by Cognigy?
- AI Agent Studio
- Agent Copilot & Agent Copilot Whisper
- Voice Gateway Integration
- Barge-In Support Agents
| Cognigy – Company & Services Profile | |
| Years in Business | 9 years |
| Core Expertise | Enterprise Conversational AI Contact centre automation |
| Tech Stack | Low-code NLP/Voice platform Multichannel bots |
| Deployment | On-premise, private cloud, or SaaS |
| Integration | Genesys, AWS, SAP, NICE, or Salesforce |
| Security | SOC2, ISO, sensitive data controls |
| Industries Served | Banking/Insurance, Telecom, Retail, Travel |
| Primary Locations | Germany & USA |
How much does Cognigy charge for AI Voice Agent development?
Cognigy charges a $43080/year for 5K conversations along with $53916 for Voice Gateway
8. Bland AI
Best for: Businesses that require High-Scale Voice AI Agents
Bland AI is a San-Francisco-based voice AI startup building an enterprise-grade platform for AI phone calls.
Bland’s platform allows companies to create, train, and deploy realistic voice agents for high-volume customer support, sales, and scheduling calls.
Its key differentiator is a focus on enterprise readiness. This typically means Bland built its own optimized TTS/ASR models, a specialized conversational language for safety or guardrails, and extensive observability tools.
What are the key AI Agent Development services offered by Bland AI?
- Pathways Workflow Engine
- Enterprise-Scale Voice Agent Deployment
- AI Safety / Guardrail Implementation
| Bland AI – Company & Services Profile | |
| Years in Business | 2–3 years |
| Core Expertise | High-performance AI voice agents |
| Tech Stack | Low-code NLP/Voice platform Multichannel bots |
| Deployment | On-premise, private cloud, or SaaS |
| Integration | ERP, CRM, schedulers via API |
| Security | Fully isolated infra |
| Industries Served | Finance, Healthcare, Logistics, QSR, Gaming, Enterprises |
| Primary Locations | GUSA |
How much does Bland AI charge for AI Voice Agent development?
Bland AI charges around $0.09/min for active calls.
9.PolyAI
Best for: Teams that need Multilingual Call Center AI
PolyAI is a leading conversational AI company founded in 2017. This enterprise AI voice agent development company is built to focus solely on voice-first customer support agents
The platform’s core product is a voice AI platform that deploys human-like automated call agents to handle support calls. It uses a technology that offers lifelike speech, high comprehension of natural dialogue, and seamless handoff to human agents when needed.
What are the key AI Agent Development services offered by PolyAI?
- Voice-First AI Support Agents
- Seamless Human Handoff Agents
- Multilingual Support Agents
| Bland AI – Company & Services Profile | |
| Years in Business | 8 years |
| Core Expertise | Voice-first customer support AI High-touch automation |
| Tech Stack | Proprietary conversational AI |
| Deployment | Cloud (SaaS) |
| Integration | Existing call platforms and databases |
| Security | GDPR, PCI |
| Industries Served | Hotels, Telecom, Banking, Insurance, Public Sector |
| Primary Locations | UK |
How much does PolyAI charge for AI Voice Agent development?
PolyAI charges enterprises through custom annual contracts, starting at about $150K/year, with add-ons costing extra.
10. Voiceflow
Best for: Businesses that aim for Rapid AI Voice Agent App Development
Voiceflow provides a popular collaborative platform for designing and building conversational AI agents, including voice-call agents.
In fact, large companies in industries like tech, education, and customer service use Voiceflow to prototype and deploy voice bots and interactive voice responses.
Voiceflow is delivered as cloud SaaS connecting to telephony carriers for call deployment. This voice app development company is also well-known for its visual drag-and-drop editor, version control, templates, and integrations with Google Dialogflow or custom LLMs.
What are the key AI Agent Development services offered by Voiceflow?
- Voice AI Receptionist Agents
- Voice Forms (Conversational Forms)
- AI Case Bot Agents
- Multi-Channel Agent Publishing
| Voiceflow – Company & Services Profile | |
| Years in Business | 6 years |
| Core Expertise | Voice-first customer support AI Collaborative AI agent design Prototyping |
| Tech Stack | Visual flow builder + APIs Supports any AI model |
| Deployment | Cloud (SaaS) |
| Integration | LLMs + telephony via API |
| Security | SOC |
| Industries Served | Tech, Customer Support, eCommerce, Education |
| Primary Locations | Canada |
How much does Voiceflow charge for AI Voice Agent development?
Voiceflow comes in 3 different packages:
- Starter: Free
- Pro: $60/mo
Business: $150/mo
How To Choose The Right AI Voice Agent Development Company
There are 1000s of voice agents in the market and a 100 more are built every day. A few of them come with flashy features, while others meet the core requirements. Now, among this large pool of options, which one should you choose?
Here is a quick list of criteria you need to analyse and find which of the providers suit your business the best.
1. Experience and Expertise
Our first recommendation is to check if the provider has a proven track record of working on AI voice technologies. Have they tried and tested different features and functionalities?
Do they know which tech stack exactly fits your business needs? Just because a company mentions they develop AI voice agents, don’t go for it.
Choose the ones that understand the nuances of the technology and build the agent that exactly fits your needs.
2. Level of Customization
Pre-built AI Voice Agents are great, but not always suitable for all businesses. You simply can’t add a bot that was built on the idea of another team. It may work but not as you aim for.
Choose a provider that can build agents, while customizing it for your workflows, customer base, and brand tone.
3. Full Data Control
What if the provider takes control of what your voicebots must answer. That would turn dangerous.
You’ll need complete control of your data, while they help you build the voice assistant, without interfering with your data privacy. Make sure you choose a provider that gives total control without any compromise.
4. White-Label Options
Can you imagine your voice agent with a third-party logo on it? It would ruin your branding and dilute authenticity.
That’s why you need to choose a provider that lets you launch your AI voice agents under your own brand identity, strengthen your customer trust and help you stand out in the market.
5. Data Privacy
Launching your voicebot without adhering to global privacy standards might lead to legal complications.
Your AI voice agent partner must adhere to the regional and international regulations including GDPR or HIPAA. This way you can safeguard sensitive customer information and reduce compliance risks.
6. Full Source Code Access
Does the provider offer full access to the codebase?
When you get it, you’ll be able to have full control over the security, features, infrastructure and control, without any limitations.
7. Low Latency
When your voicebots don’t respond on time, you might lose customers. Make sure that each interaction with your voice agent feels quick, natural and seamless.
Especially, if you belong to industries like healthcare or fintech, instant response is crucial.
Editor’s Recommendation: MirrorFly
If you’re looking for a platform that combines customization, security, full data control and enterprise-grade performance, MirrorFly is the top choice among agentic AI development companies in 2025.
What sets MirrorFly apart is its Twin Deployment Model, you can either opt for a fully managed cloud SaaS or take the self-hosted on-premise route with complete source code ownership. Besides there are a bunch of reasons why MirrorFly could be your best AI voice agent development partner.
Why we recommend MirrorFly:
- End-to-end customizable AI voice agent development
- White-labeling AI Voice Agents
- Full-data control & source code access
- Self-hosting option with full source code access
- Custom security & region-specific compliance controls
Overall, if you want a solution that doesn’t lock you into a rigid SaaS model and instead gives you freedom, scalability, and control, MirrorFly is the go-to platform for building AI voice agents in 2025.
Interested to learn more about how MirrorFly can help you with your Voice Agents?
Feel free to contact our experts and get started on your project today.
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Rajeshwari is a skilled digital marketer, passionate about SEO and exploring the latest trends and tech innovations in communication and Chat APIs. With a keen eye for detail, she helps brands improve their online visibility, and she is always eager to stay ahead in the evolving digital landscape.