{
 "sym": "Vs",
 "updated": "2026-08-06",
 "verdict": "Vapi, if your engineers are building the phone line \u2014 it has handled 1B+ calls, grew enterprise revenue 10x in the year to its $50M Peak XV Series B (May 2026), and runs 100% of Amazon Ring's inbound support. Retell is the pick when an ops-led team wants agents live this week with transparent all-in per-minute pricing \u2014 $60M ARR on ~$5M raised is the category's efficiency story. ElevenLabs Agents wins on voice quality and the cheapest credible entry ($0.08/min); Sierra when you're enterprise-scale and want to pay per resolution, not per minute; Bland when you want one flat rate and a VPC-deployable full stack. Whoever you pick: deploy voice behind chat, not before it \u2014 tolerance for failure is lower on the phone.",
 "top5": [
  {
   "rank": 1,
   "name": "Vapi",
   "maker": "Vapi (YC W21)",
   "url": "https://vapi.ai",
   "docs": "https://docs.vapi.ai",
   "pricing": "$0.05/min platform + models/voices at cost ($0 BYOK) \u00b7 10 concurrent lines incl., +$10/line/mo \u00b7 HIPAA +$2k/mo, zero-retention +$1k/mo \u00b7 enterprise volume-based",
   "best_for": "Developer teams who want full control of the voice stack \u2014 pick your own STT/LLM/TTS, test it, and ship a production support line as code.",
   "why": "The developer default: 1B+ calls handled and enterprise revenue up 10x in the year to its $50M Series B (Peak XV, with M12 and Kleiner Perkins, May 12, 2026; $72M total). Amazon Ring routes 100% of inbound calls through it. The 2026 platform run \u2014 Monitoring (Apr), Model Intelligence with production-data model recommendations (Jul), agent test suites \u2014 is the deepest tooling in the category.",
   "watch": "Orchestration-only means you own the debugging across four vendors' models. Add-ons bite: HIPAA is $2,000/mo before a single call. Ops teams without engineers ship faster on Retell or no-code tools. Series B valuation undisclosed.",
   "evidence": [
    {
     "stat": "$50M Series B led by Peak XV, $72M total raised (May 12, 2026)",
     "src": "https://vapi.ai/blog/series-b"
    },
    {
     "stat": "1B+ calls handled; enterprise revenue 10x YoY; Ring at 100% of inbound (May 2026)",
     "src": "https://vapi.ai/blog/series-b"
    },
    {
     "stat": "$0.05/min platform fee, models at cost with BYO keys (Aug 2026)",
     "src": "https://vapi.ai/pricing"
    }
   ],
   "tile_note": "the developer default"
  },
  {
   "rank": 2,
   "name": "Retell AI",
   "maker": "Retell AI (YC W24)",
   "url": "https://www.retellai.com",
   "docs": "https://docs.retellai.com",
   "pricing": "Pay-as-you-go $0.07\u20130.31/min all-in (infra $0.055 + TTS + LLM menu) \u00b7 20 concurrent incl. \u00b7 $10 free credit \u00b7 AI QA +$0.10/min \u00b7 enterprise custom",
   "best_for": "Ops-led teams who want production support agents this week \u2014 dashboard-built, transparent per-minute menu pricing, monitoring and QA included.",
   "why": "The capital-efficiency outlier: $60M ARR by April 2026 (650% YoY) on roughly $5M ever raised, running 40M+ real-time AI phone calls a month. Its 2026 releases \u2014 the Conductor agent runtime, MCP server, and the vCX-Hard benchmark (best model clears only ~88% of hard contact-center turns, Jun 2026) \u2014 show a team publishing honest evals of its own stack.",
   "watch": "A ~$5M war chest against $11B-and-up rivals is a real asymmetry if the category turns capital-intensive. Component pricing stacks: knowledge base, PII redaction, and QA add-ons push the effective rate toward the top of the range. ARR and call-volume figures are Sacra-sourced, not company-published.",
   "evidence": [
    {
     "stat": "$60M ARR, +650% YoY (Apr 2026); ~$45M end of 2025",
     "src": "https://sacra.com/c/retell-ai/"
    },
    {
     "stat": "40M+ real-time AI phone calls per month; $4.6M seed (Aug 2024) is nearly all it has raised",
     "src": "https://sacra.com/c/retell-ai/"
    },
    {
     "stat": "vCX-Hard benchmark: best of 27 models clears only ~88% of hardest contact-center turns (Jun 4, 2026)",
     "src": "https://www.retellai.com/blog"
    }
   ],
   "tile_note": "ops-ready call automation"
  },
  {
   "rank": 3,
   "name": "ElevenLabs Agents",
   "maker": "ElevenLabs",
   "url": "https://elevenlabs.io/agents",
   "docs": "https://elevenlabs.io/docs/agents-platform/overview",
   "pricing": "Free 15 min/mo \u00b7 Starter $6/mo (75 min) \u00b7 Creator $22 (275 min) \u00b7 Pro $99 \u00b7 Business $990 (12,375 min) \u00b7 overage $0.08/min; LLM/telephony at cost",
   "best_for": "Teams for whom the voice itself is the product \u2014 best-in-class synthesis, 70+ languages, and the cheapest credible entry into phone support.",
   "why": "The best voices in the business now bundled with an agent runtime: 4M+ agents deployed, phone/web/WhatsApp channels, and Eleven v3 Conversational (Feb 2026) tuned for turn-taking. Backed by an $11B company \u2014 $500M Series D, Feb 4, 2026 \u2014 so the model layer keeps compounding. At $0.08/min flat overage it undercuts most pure-plays.",
   "watch": "The agents platform is younger than the pure-plays; contact-center depth (warm transfers, compliance workflows, QA tooling) trails Vapi and Retell. Company attention is split across music, dubbing, and TTS \u2014 support agents are one product among many. Case-study stats (83.4% resolution, 4.6/5 CSAT) are vendor-published single customers.",
   "evidence": [
    {
     "stat": "4M+ agents deployed; 70+ languages, phone/web/WhatsApp/SMS (Aug 2026)",
     "src": "https://elevenlabs.io/agents"
    },
    {
     "stat": "$500M Series D at $11B valuation (Feb 4, 2026)",
     "src": "https://en.wikipedia.org/wiki/ElevenLabs"
    },
    {
     "stat": "$0.08/min overage on every tier; free tier 15 min/mo (Aug 2026)",
     "src": "https://elevenlabs.io/pricing/agents"
    }
   ],
   "tile_note": "best voices, cheapest entry"
  },
  {
   "rank": 4,
   "name": "Sierra (voice)",
   "maker": "Sierra (Bret Taylor)",
   "url": "https://sierra.ai",
   "docs": "https://sierra.ai/platform",
   "pricing": "Outcome-based \u2014 pay per resolution, enterprise contracts only, no public rate card",
   "best_for": "Enterprises that want one agent across chat and phone, paid by resolved conversation rather than by the minute.",
   "why": "Voice surpassed text as Sierra's primary channel by October 2025 \u2014 the strongest signal that phone is where enterprise agent spend is going. $200M ARR by May 2026 (from $26M end-2024), a $950M Series E at $15.8B (GV/Tiger, May 2026), and Rocket Mortgage, SiriusXM, Vanguard, and Gap on the line. Outcome pricing puts the failure-tolerance risk on the vendor.",
   "watch": "No self-serve, no published pricing, enterprise sales cycle \u2014 startups get far more per dollar from Vapi or Retell. Outcome-based pricing only pencils at volume. Its chat side competes in element Sa; you're buying a suite, not a phone tool.",
   "evidence": [
    {
     "stat": "$200M ARR (May 2026); $950M Series E at $15.8B valuation led by GV and Tiger Global",
     "src": "https://sacra.com/c/sierra/"
    },
    {
     "stat": "Voice surpassed text as the primary interaction channel by Oct 2025",
     "src": "https://sacra.com/c/sierra/"
    },
    {
     "stat": "Outcome-based pricing: \"only pay for the value Sierra delivers\" (Aug 2026)",
     "src": "https://sierra.ai"
    }
   ],
   "tile_note": "pay-per-resolution enterprise"
  },
  {
   "rank": 5,
   "name": "Bland",
   "maker": "Bland AI",
   "url": "https://www.bland.ai",
   "docs": "https://docs.bland.ai",
   "pricing": "Start $0.14/min (no card) \u00b7 Build $0.12/min + $299/mo \u00b7 Scale $0.11/min + $499/mo \u00b7 enterprise custom, VPC/on-prem \u2014 flat all-in rate, no model pass-throughs",
   "best_for": "Regulated and high-volume teams who want one predictable per-minute price and a self-hosted, single-vendor stack.",
   "why": "The vertically integrated bet: Bland runs its own STT/LLM/TTS (Bland Speech v3, Aug 2026) in its own infrastructure, so one flat rate covers everything \u2014 \"no token charges, no surprise bills.\" $50M Series C (Jun 16, 2026; $100M+ total from Scale, Emergence, HubSpot, Dell) and 3.5M+ calls a week for Samsara, Kin Insurance, and CNO Financial.",
   "watch": "Flat rate costs more at low volume than Vapi with BYO keys ($0.14 vs ~$0.06/min). Closed stack: you take Bland's models, good or bad, and can't swap in the frontier model of the month. Valuation and ARR undisclosed.",
   "evidence": [
    {
     "stat": "$50M Series C, $100M+ total raised (Jun 16, 2026)",
     "src": "https://www.bland.ai/blog/series-c"
    },
    {
     "stat": "3.5M+ calls/week for Samsara, Kin Insurance, CNO Financial (Jun 2026)",
     "src": "https://www.bland.ai/blog/series-c"
    },
    {
     "stat": "Flat $0.11\u20130.14/min bundling STT+LLM+TTS; VPC/on-prem at enterprise (Aug 2026)",
     "src": "https://www.bland.ai/pricing"
    }
   ],
   "tile_note": "flat-rate, self-hosted stack"
  }
 ],
 "matrix": {
  "cols": [
   "Pricing",
   "Free tier",
   "Builder",
   "BYO model/voice",
   "Self-host / VPC",
   "Compliance",
   "Proof point"
  ],
  "rows": [
   [
    "Vapi",
    "$0.05/min + components at cost",
    "Trial credits",
    "API-first + dashboard",
    "Yes \u2014 any STT/LLM/TTS",
    "No (cloud)",
    "SOC 2 \u00b7 HIPAA +$2k/mo \u00b7 PCI",
    "1B+ calls; Ring 100% inbound"
   ],
   [
    "Retell AI",
    "$0.07\u20130.31/min all-in",
    "$10 credit",
    "Dashboard + API + Conductor",
    "Yes \u2014 LLM menu per-min",
    "Dedicated server (ent.)",
    "SOC 2 \u00b7 HIPAA BAA",
    "$60M ARR; 40M calls/mo"
   ],
   [
    "ElevenLabs Agents",
    "Plan minutes + $0.08/min",
    "15 min/mo",
    "No-code + SDK",
    "LLM yes; voices native",
    "No",
    "Enterprise tier",
    "4M+ agents deployed"
   ],
   [
    "Sierra (voice)",
    "Outcome-based (per resolution)",
    "No",
    "Ghostwriter + Agent SDK",
    "No",
    "No",
    "Enterprise",
    "$200M ARR; voice > text"
   ],
   [
    "Bland",
    "$0.11\u20130.14/min flat",
    "Start plan, no card",
    "Norm builder + API",
    "No \u2014 bundled own stack",
    "Yes (ent. VPC/on-prem)",
    "SOC 2 \u00b7 HIPAA \u00b7 PCI",
    "3.5M calls/week"
   ],
   [
    "Parloa",
    "Enterprise contract",
    "No",
    "AMP no-code + simulation testing",
    "Partial",
    "No",
    "ISO 27001 \u00b7 SOC 2 \u00b7 HIPAA \u00b7 PCI \u00b7 DORA",
    "Fortune 200 base; $3B valuation"
   ],
   [
    "PolyAI",
    "Enterprise contract",
    "No",
    "Agent Builder + ADK",
    "Partial (own Raven model)",
    "No",
    "SOC 2 \u00b7 HIPAA \u00b7 GDPR \u00b7 PCI",
    "100+ enterprises, 45 languages"
   ],
   [
    "LiveKit Agents",
    "OSS free + cloud usage",
    "1k agent-min/mo",
    "Code (framework)",
    "Yes \u2014 anything",
    "Yes (Apache-2.0)",
    "SOC 2 \u00b7 HIPAA (cloud)",
    "Powers ChatGPT Voice; 2.5B+ calls/yr"
   ]
  ]
 },
 "rules": [
  {
   "if": "Engineers are building your phone line and you want to swap models as the frontier moves",
   "then": "Vapi \u2014 $0.05/min platform, bring your own keys, and the best test/monitoring tooling in the category."
  },
  {
   "if": "An ops-led team needs agents in production this week with a predictable all-in rate",
   "then": "Retell for the transparent per-minute menu; Bland if you'd rather one flat rate and a single vendor to blame."
  },
  {
   "if": "Voice quality or multilingual coverage is the differentiator, or you're testing the channel on a budget",
   "then": "ElevenLabs Agents \u2014 70+ languages, the best synthesis, and a $6/mo entry no pure-play matches."
  },
  {
   "if": "You're enterprise-scale, brand risk dominates, and you want the vendor to carry failure risk",
   "then": "Sierra's outcome-based pricing; in European or contact-center-first orgs, Parloa or PolyAI."
  },
  {
   "if": "You need latency and cost control at massive scale, or refuse platform lock-in",
   "then": "Build on LiveKit Agents or Pipecat \u2014 the open-source layer under half the platforms above \u2014 accepting you now own the whole pipeline."
  }
 ],
 "field": [
  {
   "name": "Parloa",
   "maker": "Parloa (Berlin)",
   "note": "Enterprise AI Agent Management Platform for contact centers; $350M Series D at $3B (Jan 15, 2026, General Catalyst); Fortune 200 base incl. Allianz, Booking.com \u2014 the near-miss for the top 5, enterprise-only motion",
   "url": "https://www.parloa.com",
   "oss": false,
   "entry": "enterprise contract",
   "status": "active"
  },
  {
   "name": "PolyAI",
   "maker": "PolyAI (London)",
   "note": "The 2017-vintage enterprise voice pioneer; own Raven model on 1B+ conversations; $86M Series D (Dec 15, 2025); 100+ enterprises incl. FedEx, Marriott, 45 languages",
   "url": "https://poly.ai",
   "oss": false,
   "entry": "enterprise contract",
   "status": "active"
  },
  {
   "name": "LiveKit Agents",
   "maker": "LiveKit",
   "note": "Open-source realtime infra + agents framework under ChatGPT's Advanced Voice Mode; 2.5B+ calls/yr on cloud, 1k free agent-minutes/mo",
   "url": "https://livekit.com",
   "oss": true,
   "entry": "free + usage",
   "status": "active"
  },
  {
   "name": "Pipecat",
   "maker": "Daily.co + community",
   "note": "Open-source voice/multimodal agent framework \u2014 the vendor-neutral alternative to platform lock-in",
   "url": "https://pipecat.ai",
   "oss": true,
   "entry": "free",
   "status": "active"
  },
  {
   "name": "Deepgram Voice Agent API",
   "maker": "Deepgram",
   "note": "STT+LLM+TTS in one API at $4.50/hr (~$0.075/min); self-host and in-VPC options from a speech-recognition incumbent",
   "url": "https://www.deepgram.com/product/voice-agent-api",
   "oss": false,
   "entry": "$4.50/hr",
   "status": "active"
  },
  {
   "name": "OpenAI Realtime API",
   "maker": "OpenAI",
   "note": "The model layer under many platforms above \u2014 gpt-realtime speech-to-speech GA Aug 28, 2025 at $32/1M audio input tokens, 20% cheaper than preview; a build-direct option for the ambitious",
   "url": "https://openai.com/index/introducing-gpt-realtime/",
   "oss": false,
   "entry": "usage (tokens)",
   "status": "active"
  },
  {
   "name": "Synthflow",
   "maker": "Synthflow (Berlin)",
   "note": "No-code enterprise voice agents, Accel-backed; 65M+ calls handled; Freshworks partnership automated 65% of routine calls",
   "url": "https://synthflow.ai",
   "oss": false,
   "entry": "pay-as-you-go",
   "status": "active"
  },
  {
   "name": "Regal",
   "maker": "Regal.ai",
   "note": "Contact-center AI agents with forward-deployed engineering; claims 97% support containment; Toyota, American Red Cross",
   "url": "https://www.regal.ai",
   "oss": false,
   "entry": "enterprise contract",
   "status": "active"
  },
  {
   "name": "Replicant",
   "maker": "Replicant",
   "note": "Contact-center automation veteran (2017); 1B+ minutes in production; steady but out-momentum'd by the 2024 wave",
   "url": "https://www.replicant.com",
   "oss": false,
   "entry": "enterprise contract",
   "status": "active"
  },
  {
   "name": "Phonely",
   "maker": "Phonely",
   "note": "SMB-tier AI phone answering; 10,000+ customers, 120k+ calls/day; free 100-minute trial",
   "url": "https://www.phonely.ai",
   "oss": false,
   "entry": "free trial",
   "status": "active"
  },
  {
   "name": "Thoughtly",
   "maker": "Thoughtly",
   "note": "Voice-led lead follow-up (call + SMS + email) \u2014 support-capable but sales-motion-first; edges toward the outbound elements",
   "url": "https://thoughtly.com",
   "oss": false,
   "entry": "demo/quote",
   "status": "active"
  },
  {
   "name": "HappyRobot",
   "maker": "HappyRobot",
   "note": "Vertical voice agents that won logistics first, now 150+ enterprises across utilities/airlines/insurance; Series C closed 2026; 10M+ interactions/mo",
   "url": "https://www.happyrobot.ai",
   "oss": false,
   "entry": "enterprise contract",
   "status": "active"
  },
  {
   "name": "Vocode",
   "maker": "community (MIT, ex-YC W23)",
   "note": "Early open-source voice-agent library (3.8k stars); repo alive but openly seeking community maintainers \u2014 momentum moved to LiveKit/Pipecat",
   "url": "https://github.com/vocodedev/vocode-core",
   "oss": true,
   "entry": "free",
   "status": "fading"
  },
  {
   "name": "Cognigy",
   "maker": "NICE (acquired)",
   "note": "Enterprise conversational/voice AI acquired by NICE for a reported ~$955M (announced Jun 2025); now sold as NiCE Cognigy, 1B+ annual interactions",
   "url": "https://www.cognigy.com",
   "oss": false,
   "entry": "enterprise contract",
   "status": "acquired"
  },
  {
   "name": "Tenyx",
   "maker": "Salesforce (acquired)",
   "note": "Voice-AI startup acquired by Salesforce (Sep 2024) to power Agentforce voice \u2014 talent/tech absorbed, product gone",
   "url": "https://www.salesforce.com",
   "oss": false,
   "entry": "\u2014",
   "status": "acquired"
  },
  {
   "name": "Air AI",
   "maker": "Air AI",
   "note": "The viral 2023 '10\u201340 minute AI sales calls' startup; product and marketing machine vanished \u2014 the air.ai domain now belongs to defense-software firm Govini's 2026 'Air' rebrand",
   "url": "https://air.ai",
   "oss": false,
   "entry": "\u2014",
   "status": "dead"
  }
 ],
 "signals": [
  {
   "fact": "AI voice agents market ~$3.5B (2026) \u2192 $35.2B by 2033, 39.0% CAGR",
   "src": "https://www.grandviewresearch.com/industry-analysis/ai-voice-agents-market-report"
  },
  {
   "fact": "Voice overtook text as Sierra's primary channel by Oct 2025; Sierra hit $200M ARR and a $15.8B valuation ($950M Series E) by May 2026 \u2014 enterprise agent spend is moving to the phone",
   "src": "https://sacra.com/c/sierra/"
  },
  {
   "fact": "2026 funding wave across the whole stack: ElevenLabs $500M at $11B (Feb 4), Parloa $350M at $3B (Jan 15), Vapi $50M (May 12), Bland $50M (Jun 16), PolyAI $86M (Dec 15, 2025)",
   "src": "https://www.eu-startups.com/2026/01/e310-million-raise-positions-germanys-parloa-far-ahead-recent-european-enterprise-ai-agent-rounds/"
  },
  {
   "fact": "Retell reached $60M ARR (Apr 2026, +650% YoY) on ~$5M raised \u2014 voice-agent platforms can scale revenue without scaling capital",
   "src": "https://sacra.com/c/retell-ai/"
  },
  {
   "fact": "Consolidation began below the platforms: NICE acquired Cognigy (~$955M, Jun 2025); Salesforce absorbed Tenyx (Sep 2024); model layer commoditizing \u2014 gpt-realtime GA Aug 28, 2025 at 20% below preview pricing",
   "src": "https://openai.com/index/introducing-gpt-realtime/"
  },
  {
   "fact": "Quality ceiling is real: Retell's vCX-Hard benchmark shows the best of 27 frontier models clears only ~88% of the hardest real contact-center turns (Jun 2026)",
   "src": "https://www.retellai.com/blog"
  }
 ],
 "notes": "Scope: TTS/voice generation is element Vo \u2014 ElevenLabs appears in both tables and is judged here only on its Agents runtime. Chat-first support agents (Fin, Decagon \u2014 both added voice in 2025\u201326) stay in Sa; Sierra is ranked here because voice is now its primary channel by its own data, but it straddles both elements. Outbound sales dialers (Thoughtly, Air AI's ghost) belong closer to the outbound/sales elements. Ranking criteria: production call volume, pricing transparency, developer/ops fit for startups, and enterprise ceiling \u2014 in that order. Conflicts and weak spots: Retell's ARR and 40M calls/mo are Sacra-only (company doesn't publish); Cognigy's ~$955M price is widely reported but the primary NICE release was unreachable; Vapi and Bland valuations are undisclosed; PolyAI's 391% ROI is a vendor-commissioned Forrester study; Parloa's own press page is stale (lists only the Series B) \u2014 Series C/D figures verified via EU-Startups; Tenyx acquisition details are from general reporting, not re-verified primary sources. Air AI caveat: the air.ai domain was taken over by Govini's defense rebrand in 2026 \u2014 do not confuse the two.",
 "sources": [
  "https://vapi.ai/pricing",
  "https://vapi.ai/blog/series-b",
  "https://www.retellai.com/pricing",
  "https://www.retellai.com/blog",
  "https://sacra.com/c/retell-ai/",
  "https://www.bland.ai/pricing",
  "https://www.bland.ai/blog/series-c",
  "https://elevenlabs.io/agents",
  "https://elevenlabs.io/pricing/agents",
  "https://en.wikipedia.org/wiki/ElevenLabs",
  "https://sierra.ai",
  "https://sacra.com/c/sierra/",
  "https://www.parloa.com",
  "https://www.eu-startups.com/2026/01/e310-million-raise-positions-germanys-parloa-far-ahead-recent-european-enterprise-ai-agent-rounds/",
  "https://poly.ai",
  "https://www.eu-startups.com/2025/12/london-based-polyai-raises-e73-2-million-to-scale-its-enterprise-conversational-ai-platform/",
  "https://livekit.com/",
  "https://synthflow.ai",
  "https://www.deepgram.com/product/voice-agent-api",
  "https://openai.com/index/introducing-gpt-realtime/",
  "https://www.grandviewresearch.com/industry-analysis/ai-voice-agents-market-report"
 ],
 "element": {
  "number": 37,
  "name": "Voice Support",
  "group": "Support & Success",
  "essential": false,
  "edition": "v2026.Q3",
  "revision": "r7",
  "license": "CC BY 4.0 \u2014 cite elems.ai",
  "url": "https://elems.ai/e/vs.html"
 }
}