Ranking updated 1 September 2026Listings reviewed 30 August 202614 agencies reviewedHow we rank
AI voice agencies build systems that hold a phone conversation: answering, qualifying, booking, escalating to a person when the call needs one. It is the hardest category on this site to buy well, because a demo that sounds good in a browser tells you almost nothing about how the same system behaves on a real phone line under load.
The distinction that matters is between firms that engineer the call layer and firms that resell a platform. The first group can tell you their latency budget, how they handle a caller interrupting mid-sentence, and what happens when a carrier drops a leg of the call. The second group configures a vendor's dashboard. Both can be the right buy; the price should not be the same, and the listings below say which is which.
Teams that treat a phone line as production infrastructure and want latency, evaluation and monitoring specified before launch rather than discovered afterwards.
Franchise networks and field service operators that need an agent wired into a dispatch system, and can work with pricing quoted per call rather than as a project fee.
Contact centers and enterprises with an existing PBX or dialer that need an agent placed inside the estate they already run rather than a replacement for it.
Enterprise teams that want an agent running in production with orchestration, tool access and tracing named up front, and a fixed-budget pilot before committing to a full build.
Companies already buying automation or internal tools from a well-reviewed studio, who want a voice agent added by a team that already knows their systems.
Intake-heavy businesses that want a receptionist or qualification agent running quickly on a rolling agreement, and are buying an outcome rather than an architecture.
Small clinics, brokerages and rental businesses that want a phone receptionist deployed and looked after, and can accept a supplier built around one named individual.
Buyers with their own technical lead who need SIP and VoIP engineering hours on a voice build, and are comfortable directing an hourly offshore team.
Ahmedabad, IN
Not published
From $1k
The full reviews
The table is the summary. Below, every agency gets the complete assessment: what it is genuinely good at, where it falls short, and the facts behind its position.
Best forTeams that treat a phone line as production infrastructure and want latency, evaluation and monitoring specified before launch rather than discovered afterwards.
Softcery is the reference point for what a serious voice engagement should disclose before anything is signed. Latency is published as a budget with each stage attributed, the telephony and speech vendors are named rather than hidden behind a platform, and the service is structured as advise, then build, then operate, which matches how phone systems actually fail. The gap is commercial rather than technical. No price appears anywhere on its own site, the three-part structure means the real number only emerges after scoping, and the independent record is 12 Clutch reviews, a thinner base than several less specialized firms on this page carry. A buyer who needs a figure approved before a scoping call will not find one here.
Pros
Publishes a component-level latency budget from its own production traffic, including a p95 figure and a stall rate
Names the full stack, from LiveKit, WebRTC and SIP to Deepgram, Cartesia and Grafana monitoring
Names five clients and runs two live demos a buyer can call rather than watch
Publishes reference on-premises hardware at $4,000 to $12,000 for buyers who cannot send audio off site
Cons
Publishes no price of its own, so the only planning figure is the $10,000 minimum Clutch displays
The advise, build and operate structure means total cost only becomes clear after scoping
Twelve Clutch reviews is a thin independent record next to the larger review bases elsewhere in this ranking
HQ
Tallinn, Estonia
Team
11-50
Pricing
$10,000+ minimum, $50-$99/hr (Clutch-displayed); own site sells advisory on an availability retainer, build work per statement of work, and operations on a retainer, with no figures published
Best forFranchise networks and field service operators that need an agent wired into a dispatch system, and can work with pricing quoted per call rather than as a project fee.
Top choice
Gearvox is one of the few voice specialists in this ranking that will tell you whose phones it answers, which makes far more of its claims checkable than is normal here. Integrating with a franchise network's proprietary dispatch system so the agent can quote a live price and an arrival time is a materially harder problem than reading a script, and running an orchestration layer over Twilio and Deepgram means the build is not hostage to one agent platform. Two things a careful buyer should weigh. The practice is almost entirely franchise operations and field service, with nothing published outside it, and pay per call with no rate makes the annual cost of a busy line impossible to estimate before scoping. The company also rebranded from Data Leaders, the Retell AI directory entry that carries its call figures still links the dead domain and is stale, and several outcome counters on its own site animate up from zero and never settle on a value.
Pros
Names its deployments, including Pop-A-Lock and Wrench.com, and describes the integration work behind them
Runs its own orchestration layer and names Twilio and Deepgram directly rather than reselling one platform
Sells automated per-call QA as a standing service rather than a launch-week check
Cons
Almost all published work is franchise operations and field service, with no evidence of delivery outside it
Per-call pricing with no published rate or floor makes an engagement impossible to budget in advance
Publishes no latency, SIP or interruption-handling detail, so call-layer behaviour has to be taken on trust
Several outcome counters on its own site animate from zero and never resolve to a number
HQ
Seattle, United States
Team
Not published
Pricing
Prices per call or per booking, tied to the value of a customer call, and describes the model as pay for performance; no figure and no minimum are published
Best forBuyers who want a latency figure and a cost per connected minute in writing early, and who do not need to know which infrastructure the work runs on.
DestiLabs gives a buyer two of the three numbers that decide a voice project, latency and cost per connected minute, and pairs them with the larger of the two 5.0 Clutch scores on this page. What it withholds is the third. Nowhere does it name a telephony provider, a speech vendor or an orchestration framework, so there is no way to judge whether 1.2 seconds was achieved on infrastructure that would survive your call volume, and no way to assess how much of the build would transfer if the relationship ended. Its self-reported scale also disagrees between sources, at 50 projects and $20M of client revenue on its own homepage against 200 projects and $100M on its DesignRush profile. Treat the published latency as the opening of a technical conversation rather than a specification.
Pros
Publishes end-to-end latency and cost per connected minute on two voice case studies
Clutch shows 5.0 from 23 reviews, the larger of the two perfect scores in this ranking
Clutch publishes a $10,000 entry point and a $50 to $99 hourly band
Cons
Names no telephony, speech or orchestration vendor anywhere, so the published latency cannot be tied to a stack
Self-reported scale disagrees between sources: 50 projects and $20M of client revenue on its own site against 200 projects and $100M on DesignRush
Voice sits inside a menu that also covers computer vision and generative imagery
Publishes its own best-voice-agency listicles, which is a self-promotion signal on a page a buyer might otherwise read as research
HQ
Tallinn, Estonia
Team
11-50
Pricing
$10,000+ minimum, $50-$99/hr (Clutch-displayed); DesignRush instead shows a $10,000-$25,000 minimum and $70/hr
Best forContact centers and enterprises with an existing PBX or dialer that need an agent placed inside the estate they already run rather than a replacement for it.
For a buyer whose problem is a working contact center that now needs an AI agent inside it, Call Sandwich is the clearest fit on this page: it is the only firm here shipping a product whose job is to bridge an existing PBX to an agent. Nearly everyone else assumes a greenfield line; this one assumes a dialer, a PBX and a queue that already exist, and it has built and sells the SIP plumbing to bridge them. The evidence problem is severe. Not one client is named, the testimonials are anonymized to job titles, the logos on its partner profile do not resolve, and the advisory board page renders unsubstituted template placeholders, so 200 enterprise clients and 10 million calls stand on the company's word alone. Its agent layer also sits on a single vendor, and its own SIP product exists to route traffic into that vendor, so single-supplier risk should be priced into any contract.
Pros
Integrates with legacy contact center estates by name, including ViciDial, Avaya, Genesys and NICE inContact
Ships its own SIP switch connecting an existing PBX to a voice agent, and states official Jambonz partner status
Holds the top tier and the longest partner tenure of any Retell AI partner in this ranking
Cons
Names no client anywhere and anonymizes its testimonials, so 200 enterprise clients and 10 million calls rest on its own word
The agent layer sits on a single vendor, and its own SIP product routes traffic into that same vendor
Publishes no price and no team size, and no independent review profile was located
Its advisory board page renders unsubstituted template placeholders, so no advisor is actually named
Azumo is a sensible nearshore partner for a US buyer whose AI work is mostly conventional engineering with a model in the middle of it, and who wants the lowest rate band available in this ranking. Clutch shows 4.9 from 27 reviews, a $10,000 minimum and $25 to $49 per hour, with most engagements landing between $50,000 and $199,999. It is not an agent specialist and does not present itself as one: AI development is 35% of a mix that also covers custom software and cloud infrastructure, and no agent framework, evaluation harness or observability tooling appears in the record. Turnover comes up repeatedly in Clutch's aggregated feedback, a specific risk on a build where context has to survive across months. Ninth reflects solid delivery evidence attached to weak agent specialization.
Pros
$25 to $49 per hour, the lowest published hourly band in this ranking, shared with Simform and RTS Labs, against a $10,000 minimum
4.9 from 27 Clutch reviews, with most engagements recorded at $50,000 to $199,999
Nearshore delivery from Rosario, Argentina, in hours that overlap the US working day
Cons
AI development is 35% of the service mix per Clutch, and the firm positions as a general nearshore software partner rather than an agent specialist
Team turnover recurs in Clutch's aggregated feedback, a direct risk on a long agent project that depends on retained context
Names no agent framework, evaluation suite or observability tooling anywhere in its record
HQ
San Francisco, United States
Team
51-200
Pricing
$10,000+ minimum, $25-$49/hr (Clutch-displayed); Clutch review data shows engagements from roughly $4,200 to $70,000+. DesignRush separately shows a $50,000+ minimum and $55/hr
Best forEnterprise teams that want an agent running in production with orchestration, tool access and tracing named up front, and a fixed-budget pilot before committing to a full build.
Master of Code Global is the right choice if you want an agent in production rather than a proof of concept, and you want to see how it will be debugged before you sign: it is the only firm on this page that names an observability layer alongside LangChain, LlamaIndex, MCP, Bedrock and Vertex, and it runs its own open source orchestration framework. The 30-day fixed-budget pilot gives a priced way to test the working relationship, and 37 Clutch reviews at 4.7 offer more to check than the small five-star samples further down. Where it falls short is the small end of the market and its origin: the practice grew out of conversation design, which Clutch still records at 40% of technical focus, and a $25,000 floor at a 200 plus person firm serving Tom Ford, Burberry and T-Mobile means a modest budget is unlikely to get senior people. It sits first because specialization fit and technical depth are the criteria we weight hardest, and no other record here evidences both this concretely.
Pros
The only record in this ranking that names an LLM observability and tracing layer, LangFuse, alongside LangChain, LlamaIndex and MCP
A 30-day fixed-budget AI pilot gives a priced first step above the $25,000 minimum
4.7 from 37 Clutch reviews, and the earliest founding year published by any firm in this ranking at 2004
Cons
Chatbot and conversational AI account for 40% of technical focus per Clutch; autonomous multi-step agent work is a newer extension of a conversation design practice
A $25,000 floor at a 200 plus person agency oriented to brands such as Tom Ford, Burberry and T-Mobile; a smaller engagement risks junior staffing
Headline figures including 1B plus users engaged, NPS 56 and CSAT 9.2 are self-reported, and the founding year appears on Clutch but not on the company's own about page
HQ
Redwood City, United States
Team
Not published
Pricing
$25,000+ minimum project, $50-$99/hr (Clutch-displayed); sells a fixed-budget 30-day AI pilot with a four to five person team, price not published
Best forTechnical buyers able to judge a build proposal on its engineering merits, who are willing to take on a supplier with no public track record.
Read the service pages and Tempo Flows sounds like one of the more capable firms in this category; try to check anything and there is nothing to check. The engineering vocabulary is specific in ways that are hard to fake, including warm transfer over SIP REFER with context carried across, barge-in handling and evaluation suites run before a line goes live. Against that, a buyer committing real budget is being asked to accept a supplier with no named client, no identified person, no legal entity, no address, no published price and about four months of public partner history, whose homepage numbers sit inside an illustration. The site is also a single-page JavaScript application that renders one line of text without scripts, so none of the detail it is judged on is reachable by a crawler. It ranks here because the technical writing is real, and no higher because nothing else is verifiable.
Pros
Describes warm transfer over SIP REFER with context injection, barge-in and queue-aware routing, which is call-layer detail resellers rarely produce
Runs regression and evaluation suites before launch and versions prompt changes
Builds multi-tenant voice platforms with usage metering and billing, a service few firms here offer
Cons
Names no client, no case study and no team member, so none of the technical claims can be checked
Publishes no founding year, legal entity, address, privacy policy or terms page of its own
The dashboard figures on its homepage sit inside a decorative mockup alongside a fictional 555 phone number
Its public partner history dates only from May 2026, roughly four months of visible track record
HQ
Las Vegas, United States
Team
Not published
Pricing
No pricing published; states a delivery arc of architecture review, system design, build, hardening and evaluation, then launch and operate, at roughly six weeks to production
Best forCompanies that need a price agreed before work starts, and are buying product engineering with a voice component rather than a voice specialist.
RaftLabs is the clearest firm on this page about what a project will cost, and for a buyer who needs a number approved before a scoping call, that counts for something real. The service description also shows awareness of what breaks a phone deployment, including interruption handling, fallback and retry logic. It ranks low for two reasons. Voice is one line on a general product menu, the flagship AI agent service page names no voice vendors at all, the voice client is not named, and much of the voice content on the site is listicle material aimed at search rankings rather than at showing how anything was built. Separately, its own copy claims a 4.9 rating across 50 or more verified reviews, while the Clutch profile it cites displays 18. The score matches; the review count does not, and pricing transparency and public accountability are two of the five criteria this ranking is decided on.
Pros
Publishes fixed price bands on its own site, from $20,000 to $50,000 for a single-workflow agent
Bills fixed price with no hourly billing, so scope changes are negotiated rather than metered
Its voice service description covers interruption and fallback handling, transcription and SMS retry logic
Cons
Its own copy claims a 4.9 rating across 50 or more verified reviews, while the Clutch profile it cites displays 18
Voice is one line on a general product development menu, and the flagship AI agent page names no voice vendors
The voice client is not named, and much of the voice content is listicle material aimed at search rankings
Its about page displays logos including Vodafone, Nike and Microsoft that are implausible as direct clients at this size and price
HQ
Dublin, Ireland
Team
Not published
Pricing
Fixed-price only, no hourly billing: single-workflow agent $20,000-$50,000 over 4-8 weeks, multi-agent systems $60,000-$150,000 over 10-16 weeks, MVP work from about $10,000; Clutch shows a $10,000+ minimum and $25-$49/hr
Best forService businesses losing bookings to unanswered and after-hours calls that want named comparable clients and a fast path to a live line.
Solven suits a service business with a straightforward problem: calls are going unanswered and bookings are being lost. Named clients with outcomes attached are rarer in this category than they should be, and the habit of reviewing calls and feeding corrections back into the agent is what separates a deployment that improves over time from one that quietly degrades. What a technical buyer will not find is any account of how the call layer works. There is no latency figure, no telephony or SIP detail, no stated position on interruption handling and no infrastructure named beyond CRM connectors, and the agent layer rests entirely on one platform vendor. There is also no independent review record and no published price, so both the commercial terms and the service quality have to be established in conversation.
Pros
Publishes named client outcomes at Anytime Fitness Australia, Colourworks and Sonnabend Capital
Reviews every call and feeds corrections back into the agent, a standing evaluation loop rather than a launch check
States agents are handling real calls inside the first week
Cons
Publishes no latency, telephony or interruption-handling detail, and names no infrastructure beyond CRM connectors
The agent layer depends on a single platform vendor, with no evidence the work would be portable
No price, founding year or team size is published, and no independent review profile was located
Best forBuyers who want transfer and routing behaviour designed properly by a certified firm, and who do not need the supplier to own realtime infrastructure.
Iffort AI earns a conversation from any buyer who cares about what happens when a call has to leave the agent, because transfer and routing behaviour is where most voice deployments embarrass their owners, and it is the part this firm writes about in operating detail rather than in features. Two ISO certifications also give a compliance-minded buyer something checkable, which is scarce in this category. The limits are structural. There is no owned realtime infrastructure and delivery rests on one platform vendor, no latency figure or interruption-handling position is published, and this is an AI unit inside a marketing agency whose voice practice dates from around 2024, with a single voice case study to show for it. No pricing appears on either domain and no Clutch, DesignRush or G2 profile was located, so neither cost nor independent service record can be checked before contact.
Pros
Publishes hands-on guidance on warm against cold transfer, caller ID configuration and trigger-based handoff logic
Holds ISO 9001:2015 and ISO 27001:2022, a pairing no other agency in this ranking states
Publishes a voice case study claiming a 70% cut in false-positive assessments at AccioJob
Cons
Delivery rests on a single platform vendor, with no owned realtime infrastructure
Publishes no latency figures and no stated position on interruption handling
It is the AI arm of a 2010 marketing agency, with a voice practice dating from around 2024 and one voice case study published
No pricing is published on either domain, and no independent review profile was located
Best forCompanies already buying automation or internal tools from a well-reviewed studio, who want a voice agent added by a team that already knows their systems.
Sidetool is a well-reviewed automation and Bubble studio that added voice recently, and this ranking reflects that order. The independent record is genuinely good, 4.8 across 28 reviews is one of the larger verified bases in this category, and the multilingual transfer support recorded on its vendor's directory is more than several voice-only firms here document. But a buyer choosing on voice has almost nothing to evaluate: no case study involves a call, no telephony, latency or call evaluation detail is published anywhere, and the business is 40% mobile app development by Clutch's own breakdown. The pricing picture is contradictory too, with a flat monthly subscription on its own site against a $10,000 project minimum on Clutch, which are different commercial models rather than different numbers. It belongs in this directory; it does not belong near the top of a voice ranking.
Pros
Clutch shows 4.8 from 28 reviews, one of the larger verified review bases in this ranking
Retell AI's directory records warm and cold call transfer with English, Portuguese and Spanish support
States a six to ten week path from kickoff to deployment
Cons
Not one published case study involves a phone call
Clutch's own breakdown puts 40% of the business in mobile app development and 15% in AI
No telephony, latency or call evaluation detail is published anywhere
Its own site sells a flat monthly subscription while Clutch shows a $10,000 project minimum, two different commercial models
HQ
Doral, United States
Team
Not published
Pricing
Own site sells a flat monthly subscription for unlimited queued automations with no figure published; Clutch shows a $10,000+ minimum project size and $50-$99/hr
Best forIntake-heavy businesses that want a receptionist or qualification agent running quickly on a rolling agreement, and are buying an outcome rather than an architecture.
Agento AI is buying-an-outcome territory. The volume recorded on its platform vendor's directory is the largest shown there for any partner on this page, the named client organizations are checkable, and 30-day rolling agreements after a two to three week implementation is a low-commitment way to find out whether a voice agent works on an intake line. For a buyer who needs to understand what they are running, the record is thin to the point of absence. Nothing technical is published, no latency or interruption behaviour is stated, no call testing method is described, and the compliance page that would carry a HIPAA or call-recording position returns a 404, which matters given the fertility and legal intake work it names. Its headquarters also disagrees between sources, with a Wyoming address of the kind registered-agent services use on its own site against New York on the vendor directory, and no founding year, team size or price is published anywhere.
Pros
Retell AI's directory records 250,000 or more calls a month, the largest monthly volume shown there for any partner here
Names four client organizations across legal intake, insurance, fertility concierge and payments
States a two to three week implementation on 30-day rolling agreements, a low-commitment entry
Cons
Publishes nothing technical: no latency, no telephony detail, no interruption handling and no call testing method
Its own how-it-works and compliance pages return 404, so no HIPAA or call-recording position can be checked
Headquarters disagrees between sources, and no founding year, team size or price is published
Delivery rests on one platform vendor, and the rest of the stack it names is generic
HQ
Not published
Team
Not published
Pricing
Custom pricing scoped per engagement, a stated two to three week implementation and 30-day rolling agreements; no figures published
Best forSmall clinics, brokerages and rental businesses that want a phone receptionist deployed and looked after, and can accept a supplier built around one named individual.
For a clinic or a small brokerage, Kingstone offers two things the larger firms on this page do not bother with: named comparable clients at the same scale, and a written agreement about what the agent will and will not do before it goes live. The exposure is concentration. One person is named on the entire site, so a buyer is taking on real key-person risk with no published team size, no founding year and no address to fall back on. The build also sits a layer above Vapi, with no SIP, latency or interruption-handling detail published, so how the call behaves under load is untestable from outside. A cost article on its site quotes $5,000 to $15,000 in setup plus around $219 a month for a Vapi receptionist, but that is presented as market guidance rather than its own rate, so its price remains unpublished.
Pros
Publishes named client deployments at the scale a small business would actually buy
Listed as a solutions partner on Vapi's own directory and names ElevenLabs as a commercial partner
Sets written operating boundaries before launch and states it retains responsibility for how systems run
Cons
Only one person is named on the entire site, with no team size, founding year or address published, which is real key-person risk
The work sits a layer above Vapi, with no SIP, latency or interruption-handling detail
Every named client is a small Croatian business, while the site frames operations across the United States and Croatia
No price is published, and no independent review profile was located
Best forBuyers with their own technical lead who need SIP and VoIP engineering hours on a voice build, and are comfortable directing an hourly offshore team.
On paper Samcom has telephony depth that several higher-ranked firms lack, and it is one of very few agencies in this category willing to publish what an hour of its time costs. Two things pull it down. Its own site advertises a Clutch score of 4.9 from 74 reviews, while the Clutch profile for this company, confirmed by domain and location and opened twice during research, displays zero client reviews. An unreviewed profile is an absence of data rather than a low score, but the advertised figure does not match the source it cites, and public accountability is one of the five criteria this ranking is decided on. The second is the shape of the engagement: hourly rates at commodity levels, a $1,000 floor, no client named anywhere and a menu running from SIP stacks to Shopify is staff augmentation rather than a delivered voice system. A buyer who already has an architect and needs VoIP hours may do well here; a buyer who wants a system owned by the supplier should look higher up this page.
Pros
Names carrier-grade SIP stacks including Asterisk, FreeSWITCH, Kamailio and OpenSIPS alongside LiveKit and Pipecat
Publishes its own hourly rate card, which almost no agency in this category does
Clutch shows a $1,000 minimum project size, the lowest published entry point in this ranking
Cons
Its site advertises a Clutch score of 4.9 from 74 reviews, while the Clutch profile for this company displays zero reviews
Names no client anywhere, so sub-500ms latency, 60,000 calls a day and 500 projects are unattached claims
Hourly billing at commodity rates with a $1,000 floor is a staff-augmentation model rather than a delivered voice system
Founding year disagrees across three sources and team size disagrees between its site and Clutch, so neither is recorded
HQ
Ahmedabad, India
Team
Not published
Pricing
Publishes hourly rates: VoIP developer $25-$55/hr, AI developer $35-$75/hr, VoIP support engineer $18-$38/hr; Clutch shows $25-$49/hr and a $1,000+ minimum project size
What actually makes an AI voice agent hard to build?
Latency and interruption. A human notices a pause beyond roughly 800 milliseconds, and that budget has to cover speech recognition, the model, and speech synthesis together, over a phone connection you do not control. Handling a caller who talks over the agent, transferring a live call with context intact, and failing over gracefully when a carrier drops a leg are all engineering problems that a platform demo never shows you.
How do I tell a voice engineering firm from a platform reseller?
Ask for their latency figures from production traffic, not a benchmark. Ask which telephony stack they use and whether they run their own session border controller. Ask what happens on interruption and how a warm transfer carries context. A firm that engineers the call layer answers these immediately; a reseller redirects to features.
What should an AI voice project cost?
Build costs in this ranking run from around $10,000 for a single well-scoped call flow to six figures for a contact centre integration. Per-minute running costs are separate and often matter more at volume, so ask for both. An agency that quotes a build price without asking your call volume has not thought about your running costs.
