Quick answer
The right voice AI agency depends on your platform, your scale, and whether you want a packaged plan or a custom build. Here's the short version. The order isn't a ranking.
| Agency | Based in | Best for | Platform status |
|---|---|---|---|
| Antek Automation | Hampshire, UK | Packaged monthly voice agent plans | Retell Gold Partner |
| GIGS Consulting | Latin America | Spanish-speaking market voice AI | Retell Gold Partner |
| Hestur AI | Distributed, UK/US hours | Custom builds across Vapi, LiveKit, Retell | Not platform-exclusive |
| Master of Code Global | Redwood City, CA (6 offices) | Large enterprise conversational + voice AI | Microsoft & AWS partner |
| Data Leaders | Seattle, WA | High-volume inbound sales/service lines | Retell Diamond Partner |
| Rapid Innovation | Not published | Voice AI plus wider workflow integrations | Retell Gold Partner |
Looking for a general AI automation agency instead? See our guides for the UK and USA.
How we chose (and our conflict of interest)
Hestur wrote this guide, and Hestur is on it. Most voice AI roundups are either written by an agency ranking itself first, or are vendor lists of software platforms rather than agencies you can hire. We tried a different anchor: Vapi's and Retell's own official partner directories, since a listing there is at least evidence the agency has actually built on that platform.
That source has a real limit, and we want to be upfront about it. Unlike Clutch, these partner directories aren't independently verified review platforms; agencies submit their own listing and description. Where a directory entry included a specific, checkable claim (a call volume, a client count, a price), we've repeated it but flagged it as self-reported where we couldn't verify it elsewhere. Where we found nothing beyond the directory listing, we said so rather than filling in a guess.
We didn't rank the six. We've put ourselves in the slot where we genuinely compete: custom builds across more than one voice platform. Nobody paid to be included, and we have no referral relationship with Vapi, Retell, or any agency named here.
The 6 agencies
Each profile covers where the agency is based, who it suits, and the facts we could verify.
Antek Automation
- Based in
- Andover, Hampshire, UK
- Best for
- Trades, clinics, and professional firms that want a packaged voice agent on a monthly plan
Antek Automation is a Retell AI Gold Partner, per Retell's own Solution Partners directory, focused on UK service businesses: tradespeople, cleaning firms, estate agents, dental practices, law firms, and accountants. It builds AI voice agents, website chatbots, and workflow automation on n8n.
Its pricing is packaged and published on its own site: voice agents from £97 a month, chatbots from £57 a month, workflow automation from £250, all month to month with 30 days' notice. That's the only pricing in this guide that's a standard rate card rather than a quote.
GIGS Consulting
- Based in
- Latin America (serves the Spanish-speaking market)
- Best for
- Businesses that need voice AI built and supported in Spanish
GIGS Consulting is listed as a Retell AI Gold Partner specializing in voice AI solution development for Spanish-speaking markets. Retell's partner directory is the only public listing we could verify this against; the company doesn't appear to have an English-language site with the same level of detail.
If your customer base or call volume is primarily Spanish-speaking and you want an agency built around that from the start rather than an English-first shop adding a Spanish model, this is a narrower but relevant specialism.
Source: [1]
Hestur AI (us)
- Based in
- Distributed team serving UK and US clients, working GMT/BST and US business hours
- Best for
- Custom voice agents that need to integrate with your existing CRM, scheduling, or practice-management software, without being locked to one voice platform
We build voice AI agents on Vapi, LiveKit, or Retell, picking the platform based on what the project needs rather than selling whichever one we're a partner of. That also means we don't appear in any single platform's partner directory the way the other five agencies here do.
We work fixed scope: a proof of concept on your real call data runs $10K to $25K over 2 to 4 weeks, with production typically 6 to 10 weeks after that. We're not the right pick if you specifically want a Retell- or Vapi-certified partner for co-marketing or platform-side support; the agencies above cover that better.
Source: [3]
Master of Code Global
- Based in
- Redwood City, California, with 6 offices and 250+ staff according to its own G2 profile
- Best for
- Large enterprise brands that need conversational AI and voice assistants built with dedicated conversation design, not just a phone-answering bot
Master of Code Global is a conversational AI company whose services span chatbots, voice assistants, and generative AI integration, with every project including a dedicated conversation designer by its own description. It's an official Microsoft and AWS partner and holds a LivePerson certified-partner designation for end-to-end conversational AI services.
This is a different scale than the other agencies in this guide: DesignRush lists it at 100-249 employees, while its own G2 profile says 250+ across 6 global offices. It cites a payment-refund chatbot for a national food-services client that reduced agent escalations by 44% to 66%. That scale and process overhead suits an enterprise budget more than an SMB one.
Data Leaders
- Based in
- Seattle, Washington
- Best for
- US businesses with high inbound call volume wanting a sales- and service-focused voice AI line
Data Leaders is listed as a Retell AI Diamond Partner, Retell's top partner tier alongside Elite, focused on inbound sales and service voice AI. Retell's own directory entry for the company reports it handling 15,000+ calls a month, which, if accurate, suggests real production volume rather than pilot-scale deployments.
Beyond that directory listing, we couldn't independently verify pricing, team size, or founding year from public sources, so take the volume figure as the agency's own reported number rather than an audited one.
Source: [1]
Rapid Innovation
- Based in
- Not published in Retell's directory or readily found elsewhere
- Best for
- Businesses that want voice AI bundled with broader workflow integration work, not a standalone phone line
Rapid Innovation is listed as a Retell AI Gold Partner offering conversational AI and workflow integrations, with Retell's directory citing 180+ clients. The broader workflow-integration framing distinguishes it from the more voice-only specialists in this guide.
As with Data Leaders, we're relying on Retell's own partner directory for this entry and haven't independently verified the client count, so treat it as self-reported.
Source: [1]
Need a custom voice AI build?
That's where we fit on this list. Tell us what you want the agent to handle and we'll tell you honestly whether we're the right team, or which agency above is a better match.
Talk to usHow to choose a voice AI agency
Start with volume and complexity, not the agency's logo. A single packaged use case (after-hours answering, appointment booking) fits a monthly-plan agency like Antek. A high-volume sales or service line fits a partner built around scale, like Data Leaders. A build that has to read and write your CRM, handle multiple call types, or avoid platform lock-in is where a custom-build shop earns its higher price.
Next, ask how the agency is paid by the platform, not just by you. A platform partner program can create an incentive to recommend that platform regardless of fit. That's not disqualifying, but it's worth asking directly: would this agency build on a different platform if your requirements called for it?
Questions to ask on the first call
- Can I hear a live call recording on a use case like mine, not a scripted demo?
- Which voice platform would you use for this, and what would make you pick a different one?
- Is your partner-tier badge based on reviewed client outcomes, or just build volume on the platform?
- What happens when the AI mishears or gets something wrong mid-call?
- Who owns the voice agent configuration, prompts, and call data when the engagement ends?
If you're still deciding which underlying platform fits before you pick an agency, see Vapi vs Retell or LiveKit vs Vapi. For the broader build-vs-buy question, see an AI agency vs an in-house team.
Frequently asked questions
What is the best voice AI agency in 2026?
There isn't one best agency, there's a best fit for your platform and scale. If you want a packaged monthly plan, Antek Automation is built for that. If you need Spanish-language coverage, GIGS Consulting specializes there. If you're a large enterprise brand, Master of Code Global operates at that scale. If you want a custom build across Vapi, LiveKit, or Retell rather than a single platform's partner program, that's where we fit.
How much does a voice AI agency cost?
Most of the agencies in this guide don't publish pricing; voice AI partner directories are mostly a specialism listing, not a price list. Of the six here, only Antek Automation publishes a figure (voice agents from £97 a month, packaged). Our own proof of concept runs $10K to $25K over 2 to 4 weeks. Expect most custom builds to quote only after a scoping call.
Should I pick an agency from a platform partner directory?
It's a reasonable starting filter, not a guarantee. A Gold, Elite, or Diamond badge on Vapi's or Retell's partner page means the agency has built on that platform and the platform vendor has some relationship with them. It doesn't mean independent client reviews, a verified location, or published pricing, all three of which are far rarer in these directories than on Clutch. Treat the badge as a shortlist filter, then verify the rest yourself.
Vapi vs Retell vs LiveKit: does it matter which my agency uses?
It affects cost and control more than call quality. Retell and Vapi are managed platforms with per-minute platform fees on top of your own model and telephony costs. LiveKit is open-source infrastructure you self-host, which suits teams that want full control or have strict data residency needs, at the cost of more engineering to run it. A good agency will tell you which fits your constraints instead of defaulting to the one they're a partner of.
Why is Hestur on its own list?
Because we build voice AI agents and we'd be a credible option for some readers. We're not a single-platform partner; we build on Vapi, LiveKit, or Retell depending on what the project needs, which is also why we aren't listed in either vendor's partner directory the other five agencies here come from. We've said plainly where we do and don't fit.
Sources
All facts were checked against these pages in October 2026. Partner directories and agency sites change often, so confirm current details directly before you buy.
- [1] Retell AI Solution Partners directory (Antek Automation, GIGS Consulting, Data Leaders, Rapid Innovation listings): https://retellai.com/partners
- [2] Antek Automation: homepage (address, Retell partnership, pricing): https://www.antekautomation.com/
- [3] Hestur AI: Voice AI services: https://hestur.co/services/voice-ai
- [4] Master of Code Global: Conversational AI Services (own site): https://masterofcode.com/conversational-ai-services
- [5] Master of Code Global on G2 and DesignRush (office count, staff size, partner status): https://www.g2.com/products/master-of-code-global/discuss