Best Voice AI & AI Agent Development Companies (2026)

By Zeeshan Sikander, Founder & CEO of Zenkoders · Published November 2026 · Company details checked on 11 November 2026

Quick answer: The best voice AI and AI agent development company depends on what you are building. For AI phone receptionists and voice agents connected to your CRM and calendar, look at Zenkoders, Fora Soft and Trembit. For voice AI inside a WebRTC or real-time product, look at WebRTC.ventures. For fixing latency or moving off a platform, look at Softcery. For enterprise agentic AI, look at Intellectyx, LeewayHertz and Markovate. For fixed-scope AI agents and automation, look at RaftLabs.

Disclosure: This guide is published by Zenkoders, and we include ourselves. To keep it fair, we have not given the companies numbered ranks. We grouped them by what each one is best for. Facts about other companies come from their own websites, checked in November 2026. None of them was contacted, and none paid to be included. If you spot something out of date, email us and we will correct it.

Voice AI agents can now answer calls, book appointments, qualify leads and update a CRM in a natural voice. Building one that works on real phone lines is harder than a demo suggests. Calls break on slow replies, misheard names, callers who interrupt and integrations that fail mid-booking. This guide compares development partners that build voice AI and AI agents, and explains how to choose between them.

How We Chose These Companies

• Voice or agent work on offer today: each company lists voice AI agents, AI call agents or AI agent development as a current service on its own website.
• Telephony and real-time depth: experience with phone numbers, SIP, WebRTC and real-time audio, not only chat.
• Production focus: evidence of shipped products, case studies or a published stack, not just a landing page.
• Clear public information: we could confirm what the company does and where it is based from its own site.

No independent body tests voice AI builders side by side, so treat any list, including this one, as a shortlist to check yourself.

At a Glance

Voice AI Agent Specialists

Zenkoders

Best for: AI phone receptionists and voice agents that book appointments, qualify leads and update your CRM, especially for clinics, dental practices, law firms and home-services companies.

Zenkoders is a custom software and AI development company founded in 2019. Its US entity, Zenkoders LLC, was registered in Delaware in 2022, and its engineering team is based in Pakistan. It builds voice agents on Twilio, Telnyx or Vonage phone lines, or over SIP from an existing phone system, using Vapi, Retell AI, LiveKit or Pipecat depending on cost and control needs.

• Proof: its own AIVentra voice receptionist answers in under one second, resolves 94% of calls without a human and runs with 99.9% uptime.
• Compliance: HIPAA-ready setups with PII redaction, encryption and audit logs.
• Timeline: pilots typically go live in 4 to 6 weeks.
• Reviews: 5.0 on Clutch from 30 verified reviews (Zenkoders on Clutch).
• Keep in mind: the team works offshore with US-hours overlap rather than from a US office, and its Clutch profile is smaller than those of agencies that have been around longer.

See Zenkoders’ voice AI agent development services.

Fora Soft

Best for: AI call agents and voice assistants built by a team with long experience in video and real-time software.

Source: Fora Soft website (checked November 2026)

Fora Soft describes itself as a specialist software house for video, real-time and AI products, founded in 2005 with 50+ in-house specialists. Its services include AI call agent development, LiveKit AI agent development, voice assistants, speech-to-text, text-to-speech and voice cloning, and AI simultaneous interpretation.

• Keep in mind: its website lists service names but few details on how voice projects are delivered, so ask for voice-specific case studies.

Trembit

Best for: voice assistants inside apps that also need video, telehealth or live chat.

Source: Trembit website (checked November 2026)

Trembit offers full-cycle custom software development and lists 15+ years of experience and 50+ engineers. Its AI services include AI voice assistant development and AI agents, alongside video streaming and WebRTC work on Janus and Mediasoup. It names Twilio and Vonage among its partners.

• Keep in mind: its homepage does not list office locations, so confirm where your team would sit and the time-zone overlap.

WebRTC.ventures

Best for: adding voice AI to a real-time communication product, such as video calls, contact centers or telehealth.

Source: WebRTC.ventures website (checked November 2026)

WebRTC.ventures is headquartered in Charlottesville, Virginia, with a QA center in Panama City, and has focused on custom WebRTC development for over a decade. It adds voice AI, AI agents, transcription, translation and sentiment analysis to real-time apps, and partners with LiveKit, Vonage, SignalWire, Daily and Amazon Chime SDK. It is also an AWS Partner.

• Keep in mind: it is strongest when voice AI is part of a wider real-time product, less so for a simple standalone phone receptionist.

Softcery

Best for: B2B software companies that already run voice agents and need lower latency, more natural conversations or a move off a hosted platform.

Source: Softcery website (checked November 2026)

Softcery is a voice AI consultancy based in Tallinn, Estonia. It focuses on latency, naturalness, reliability, self-hosting and model evaluation, and licenses its own conversational AI stack with full source code. It publishes its prices: audits from $4,000, advisory from $4,000 a month and sprints from $8,000.

• Keep in mind: it works mainly with B2B software companies, so a small business wanting a ready receptionist may be a less natural fit.

AI Agent and Automation Builders

RaftLabs

Best for: fixed-scope AI agents and workflow automation for small and mid-sized companies.

Source: RaftLabs website (checked November 2026)

RaftLabs, with offices in Dublin, Ireland and Ahmedabad, India, builds custom software, web and mobile apps, AI agents and workflow automation. It says it adds supervised AI where it helps and keeps human approval where judgment matters. It also takes over prototypes built with tools like Lovable, Replit, Bolt and v0.

• Keep in mind: voice is not the main focus on its homepage, so ask for phone-agent examples if calls are central to your project.

Intellectyx

Best for: enterprises that want agentic AI designed, built and then operated for them.

Source: Intellectyx website (checked November 2026)

Intellectyx calls itself an enterprise agentic AI innovation and delivery partner. It is headquartered in Pasadena, California, with an office in Denver, and says it has 16 years in operation. Beyond building custom AI and agentic systems, it offers AgentOps as a managed service. Its flagship industries are manufacturing and financial services.

• Keep in mind: its homepage centers on enterprise agentic AI rather than voice, so confirm voice experience for phone projects.

LeewayHertz

Best for: enterprises that want AI agents built on a governed platform.

Source: LeewayHertz website (checked November 2026)

LeewayHertz builds generative AI and AI agent solutions for startups and enterprises, including single-agent and multi-agent systems using tools like crewAI and AutoGen Studio. It offers ZBrain, which it describes as a governance-first agentic AI platform. Its website reports that The Hackett Group has acquired LeewayHertz.

• Keep in mind: projects may lean on its own platform, so check how portable the finished agents are.

Markovate

Best for: AI agents and conversational AI for manufacturing, construction, healthcare, insurance and real estate.

Source: Markovate website (checked November 2026)

Markovate offers AI consulting, generative AI development, AI agent development and forward-deployed engineers, and lists conversational AI for customer- and employee-facing use. It also has its own AI Blueprint Classifier product for drawings.

• Keep in mind: its homepage does not list voice AI or a location, so ask about phone-agent work and where the team is based.

Agency or Platform: Which Do You Need?

Voice AI platforms such as Vapi, Retell AI, Synthflow, Bland AI and PolyAI let you build agents without a full development team. A platform is often enough if your call flow is simple and you have someone to configure and test it. An agency makes sense when the agent must connect to your CRM, calendar, practice-management software or phone system, when you need HIPAA or other compliance controls, or when you want someone to monitor and improve calls after launch. Many agencies, including several above, build on these platforms rather than replacing them. For what a custom build involves, read our guide to AI voice receptionist development.

How to Choose a Voice AI Development Partner

1. Ask for a live call, not a video. Call a voice agent the company has already shipped and test interruptions, accents and unexpected questions.
2. Ask for measured latency. Callers notice delays above about one second. Ask for numbers from a delivered agent, not a target.
3. Check telephony experience. Phone numbers, SIP trunks, call transfers and recording consent cause more problems than the AI model.
4. Confirm compliance. For healthcare, ask which providers will sign a BAA and where audio and transcripts are stored.
5. Clarify ownership. Find out who owns the prompts, integrations and accounts, and whether you can move platforms later.
6. Start with a pilot. A 4 to 6 week pilot on one call type shows quality and cost before a full rollout.

For budgeting, see our guide to AI agent development cost.