Best voice AI development companies in the US (2026)
The best voice AI firm has agents on real calls today, and hands a caller to a person when it should. We rank on that.
The short answer
SoundHound AI is the strongest pick if you're a large chain or enterprise that wants a vendor-run voice agent at scale. Most small and mid-size firms need the call built around their own systems instead.
You get SoundHound's scale with its limits: its platform, its rules and its roadmap. Want the agent written into your own calendar, CRM and transfer rules? A custom build from Hashlogics does that, and we keep running it after launch. The trade-off is that it's built for you, not switched on. See how we build voice agents.
Hashlogics builds voice agents for clients, so we are one of the companies on this list. We are ranked second by the criteria below, and the disclosure sits in the method.
Key takeaways
3 things that decide this
- 01SoundHound AI ranks first for large chains and enterprises. Hashlogics ranks second, for firms that need the agent built into their own systems.
- 02Every company was ranked on five checks: live production calls, who builds the call flow, handoff design, ownership after launch and fit for your size.
- 03Before you hire anyone, ask to hear a real call.
Four signals to test on any vendor
Run these on any shortlist, in order. Most vendors stop answering well by the second one.
An agent on live calls
Ask to hear a real call, not a scripted demo. A live agent has handled interruptions, noise and a caller who changes their mind mid-sentence.
Outbound calls that finish a task
Inbound answering is the common pitch. Ask whether the agent can place a call, get an answer and bring it back to your staff.
A designed handoff
Ask what the agent does when a caller wants a person or reports an emergency. The answer should be a written rule your team agreed, not a prompt.
Transcripts you can see
Ask who sees each call afterward, and from where. You should be able to pull up any transcript during a dispute, across every location.
How we ranked
Verified
We scored every company on the five criteria below. On 11 November 2026 we checked each company's own site and its Clutch profile where it has one. We also checked its headquarters, founding year and named clients. Every company here is headquartered in the US.
Four of the six are product companies, not service firms, so Clutch doesn't list them. We ranked them on what their own pages show. Our own criteria come from building and running voice agents that take live customer calls.
Hashlogics publishes this page. We are listed where the criteria put us. No company paid for its place.
- Live production calls
- Named clients whose real inbound or outbound calls the agent handles today.
- Who builds the call flow
- Whether the company designs the flow around your systems, or hands you a console to build it.
- Handoff design
- A written rule for when a caller reaches a person, tested before launch.
- Ownership after launch
- Who sees the transcripts and who changes the flow once the agent is live.
- Fit for your size
- Whether a small business, a mid-size firm or an enterprise contact center is who it serves.
The six companies at a glance
Facts checked on 11 November 2026 on each company's own site and on Clutch.
| Company | HQ | Founded | Clutch (rating, reviews) | Best for | Not for |
|---|---|---|---|---|---|
| SoundHound AI | Santa Clara, CA | 2005 | No Clutch profile | Restaurant chains and enterprises | Teams wanting to own the call logic |
| Hashlogics | Lahore engineering, New York office | 2017 | see clutch.co/profile/hashlogics | Agents built into your own systems | One simple call type, no system writes |
| Cresta | Sunnyvale, CA | 2017 | No Clutch profile | Enterprise contact centers | Businesses without a contact center |
| Retell AI | Redwood City, CA | 2023 | No Clutch profile | Teams building their own agents | Buyers wanting the flow built for them |
| Vapi | San Francisco, CA | 2020 (as Superpowered) | No Clutch profile | Developers wanting control of each layer | Teams without engineers |
| Bland AI | San Francisco, CA | 2023 | No Clutch profile | Regulated, high-volume call lines | Teams picking their own speech vendors |
Ranked
Best fit first by the five criteria above. Each entry names who it suits and who it doesn't.
Vendor-run voice agents at restaurant and enterprise scale
SoundHound AI is a public company in Santa Clara, California, founded in 2005. It runs voice AI agents on its OASYS platform for restaurants, car makers and contact centers. Its site names Five Guys, Chipotle, Jersey Mike's, Stellantis and Verizon among its customers.
If you run a chain, you buy a product that already takes phone orders at scale. You also accept its platform and its roadmap, and you don't write the call logic yourself.
Best for
- Restaurant chains taking phone and drive-thru orders
- Enterprises wanting a vendor to run the agent
Not for
- Businesses that need the call written into their own booking system
- HQ
- Santa Clara, CA
- Founded
- 2005
Voice agents built into your systems, and run after launch
Hashlogics designs the call flow around your business and writes it into your calendar or CRM. We keep running it after launch under an SLA or a trained handover. Senior engineers build it, with founder-level attention on every project. We run ZhoopZhoop's AI receptionist, which answers and books calls for a multi-branch auto repair business. Its outbound agents call parts suppliers and bring back a comparison.
GreetKeeper, our own AI phone receptionist, answers at any hour, books into your calendar and transfers to your team when a caller asks. You can read both builds among our 22 published case studies. Every project starts with a free scoping call and a fixed-fee Blueprint, credited in full against the build. If the plan isn't one you'd act on, you don't pay for it.
Best for
- Small and mid-size firms whose calls must book, route or escalate
- Multi-location businesses sharing one number
Not for
- A single simple call type with nothing to book, where a platform alone is enough
- HQ
- Lahore engineering, New York office
- Founded
- 2017
- 03
Cresta ↗
AI agents and live assist for enterprise contact centers
Cresta was founded in 2017 as a spin-out of the Stanford AI Lab and is based in Sunnyvale, California. It sells AI agents for voice and chat alongside real-time assist for human agents, and calls itself an enterprise customer experience platform.
Its named customers include United Airlines, Alaska Airlines, Marriott, Hilton, Verizon and CVS. If you run a large contact center with human agents, it fits that shape.
Best for
- Enterprise contact centers mixing AI agents with human staff
Not for
- Small businesses with no contact center to staff
- HQ
- Sunnyvale, CA
- Founded
- 2017
A voice agent platform your team builds on
Retell AI was founded in 2023 and is based in Redwood City, California. It sells a voice agent platform with APIs, SDKs and a visual flow builder. Retell says most of its production minutes run through agents its customers build and manage themselves.
Named customers include Anker, Matic Insurance and SelectQuote. If you have someone to build and tune the agent, it's a strong base. If you don't, you'll need a builder on top.
Best for
- Teams with staff to build and manage their own agents
Not for
- Buyers who want the call flow designed and run for them
- HQ
- Redwood City, CA
- Founded
- 2023
- 05
Vapi ↗
Developer-first voice agent infrastructure
Vapi is based in San Francisco. Its founders started the company as Superpowered in 2020 and moved it to voice AI in 2023. Vapi sells an API-first platform where developers choose each layer, from telephony to the voice.
Its site names customers such as Amazon Ring, Intuit and New York Life, among others. You get control of every piece, and your engineers carry the build.
Best for
- Engineering teams that want control of each layer
Not for
- Teams without developers to build and test the flow
- HQ
- San Francisco, CA
- Founded
- 2020
Self-hostable phone agents for high-volume calls
Bland AI was founded in 2023 in San Francisco and went through Y Combinator. It runs phone agents for inbound and outbound calls on its own models and infrastructure, with self-hosted and on-premises options.
Idaho Housing and Finance Association is one named customer, using Bland to verify callers and transfer them. If your calls are regulated and high volume, look here.
Best for
- Regulated, high-volume inbound and outbound call lines
Not for
- Teams that want to pick their own speech and model vendors
- HQ
- San Francisco, CA
- Founded
- 2023
- Live?A real call, not a demo line.
- Outbound?Can it finish a task on a call it places?
- Refuses?What triggers a transfer, in writing.
- Visible?Who sees the transcript after.
A firm running voice agents in production answers all four questions without preparation.
When a platform alone is the right call
A platform on its own is a fair choice for a single, simple call flow. An FAQ line, a basic appointment reminder, a script that never touches another system. Paying a development company to build that is overkill.
That changes once the call has to write to a calendar or CRM, route by branch, or hand off correctly on the calls that matter. Wiring those systems together is engineering, not prompt writing. It shows up fastest on the calls a business cannot afford to get wrong.
- 01One call type, no system writes? A platform and an afternoon may be enough.
- 02Calls that book, route or escalate? Someone has to design and test that path.
- 03Multiple locations sharing one number? Visibility across branches becomes the real product.
Voice agents answering real customer calls
Testing a shortlist of voice AI vendors?
Ask us the same four questions and compare our answers with the rest. We will also say when a platform alone would serve you better. The call is free; a build starts with a fixed-fee Blueprint, credited in full against the build.
Questions buyers ask
01What is the best voice AI development company in the US?+
For large chains and enterprises that want a vendor-run agent, SoundHound AI is the best pick. Hashlogics ranks second, for a firm that needs the agent built into its own systems.
02Who are the best voice AI development companies for a small business?+
A small business needs one phone line answered well and a person reachable when it matters. A builder that runs the agent after launch fits that shape. For one simple call type with nothing to book, Retell AI or Vapi may be enough on their own.
03What are the best voice AI development companies for a mid-size company?+
A mid-size company with a contact center should look at Cresta, which is built for human and AI agents together. If you run several branches on one number and need bookings written into your own systems, a custom builder fits better.
04How do I compare voice AI development companies fairly?+
Score every company on the same five checks: live calls, who builds the flow, handoff design, ownership after launch and fit for your size. Then ask each to play you a real call.
05How were these companies ranked?+
We checked each company's own site, Clutch, HQ, founding year and named clients on 11 November 2026, then scored five criteria. Hashlogics publishes this page, is listed where the criteria put it, and no company paid for its place.
06How much does it cost to hire a voice AI development company?+
There is no honest number until someone reads your call flows and systems. Three things set it: call minutes, telephony and the integrations the agent writes to. Our guide to AI agent project costs explains each one. A fixed-fee Blueprint, credited in full against the build, turns them into a fixed price per milestone.
07What is the difference between a voice AI platform and a voice AI development company?+
A platform like Vapi, Retell or Bland gives you telephony, speech recognition and a place to build the agent. A development company builds the call flow on pieces like Twilio, Deepgram and ElevenLabs voices. It connects that flow to your calendar or CRM and stays accountable for how it behaves. Many development companies build on top of a platform rather than replacing it.
08Can I just use a platform directly instead of hiring anyone?+
For one simple call type with no system to write to, yes. Once the agent needs to book a real slot or route between locations, someone has to design and test that logic. A platform login does not do that part for you.
09How do we test a voice AI vendor before committing?+
Ask to hear a real call from a live deployment, not a scripted demo. Then ask what the agent does when a caller wants a human or reports something urgent. A vendor with production experience answers both without hesitating.
10What happens to the call recordings and transcripts?+
They should be stored and visible to your staff, not locked inside the vendor's own dashboard with no export. Ask where transcripts live and who can pull one up during a dispute, before the system goes live.
11Why did you leave out PolyAI and Parloa?+
PolyAI is headquartered in London and Parloa in Berlin, and this list ranks US-headquartered companies. Speech providers like Deepgram sell the layer agents run on, not the agent, so they're not ranked either.
Related reading
- Voice AI agents →How we build and run voice agents on live phone lines.
- Voice AI platform vs a custom build →When Vapi or Retell alone is enough, and when it is not.
- What does an AI agent project actually cost? →The drivers that set the price, without a made-up range.
- AI agent development →How we build agents that take real actions, including on the phone.
- Should an AI receptionist handle emergency calls? →The escalation rules a voice agent needs before launch.
- ZhoopZhoop case study →ZhoopZhoop's AI receptionist and outbound procurement agents, the build this page draws on.
- Best AI agent development companies →The same test, applied to agents beyond the phone.
