Best Realtime Voice Agent APIs

Best overall: ElevenLabs Conversational AI (ElevenAgents)

████████░░ 81 / 100 data score

ElevenLabs Conversational AI (ElevenAgents) is a real-time voice agent platform for building inbound and outbound phone automation, covering use cases from customer support and appointment scheduling to healthcare answering services and sales calls. Pricing starts at $0.08 per minute with a free tier of 15 minutes per month, scaling through self-serve plans up to enterprise; telephony costs are billed separately. The platform holds SOC 2 Type 2, HIPAA, GDPR, ISO 27001, and PCI DSS certifications, with SDKs for Python, TypeScript, React, React Native, and Kotlin, plus an MCP server and support for bring-your-own LLM and voice.

From $0.08 minute · free tier available.

How it stacks up

• ✓ OpenAI Realtime API (gpt-realtime) starts lower at $0.02 per minute vs $0.08 for ElevenLabs Conversational AI (ElevenAgents).
• ✓ Telnyx Voice AI Agents starts lower at $0.05 per minute vs $0.08 for ElevenLabs Conversational AI (ElevenAgents).
• ✓ Twilio ConversationRelay starts lower at $0.07 per minute vs $0.08 for ElevenLabs Conversational AI (ElevenAgents).

Best for: Prototypes and side projects - free to start, no sales call; Regulated or enterprise workloads - compliance attestations and an enterprise plan; AI agents and automation - an agent-ready surface (MCP / llms.txt).

ElevenLabs Conversational AI (ElevenAgents) profile → · ElevenLabs Conversational AI (ElevenAgents) vs OpenAI Realtime API (gpt-realtime) →

At a glance

Quick pick by use case

If you only have thirty seconds, find your situation:

• If you want the strongest all-round pick, pick ElevenLabs Conversational AI (ElevenAgents) - our default pick: strongest across pricing, trust and breadth.
• If you want to start free, pick ElevenLabs Conversational AI (ElevenAgents) - free tier: Free plan at $0/month includes 15 minutes of agent calls per month, up to 4 concurrent ca….
• If you're buying for a regulated or large team, pick ElevenLabs Conversational AI (ElevenAgents) - for regulated or large teams: SOC 2 Type II, HIPAA, enterprise plan.
• If you want the lowest published entry price, pick LiveKit Agents - from $0.01 minute to start; compare on your real usage, not the entry price.
• If you're wiring this into coding agents or AI workflows, pick ElevenLabs Conversational AI (ElevenAgents) - easiest to wire up programmatically: MCP server + llms.txt.
• If you want the broadest documented surface, pick Retell AI - 29 documented actions; breadth isn't quality, but it's the most to build on.

The picks in depth

• #1 ElevenLabs Conversational AI (ElevenAgents)

  ████████░░ 81 / 100
  • Best overall
  • Best free pick
  • Best for enterprise
  • Best for agents

  ElevenLabs Conversational AI (ElevenAgents) is a real-time voice agent platform for building inbound and outbound phone automation, covering use cases from customer support and appointment scheduling to healthcare answering services and sales calls. Pricing starts at $0.08 per minute with a free tier of 15 minutes per month, scaling through self-serve plans up to enterprise; telephony costs are billed separately. The platform holds SOC 2 Type 2, HIPAA, GDPR, ISO 27001, and PCI DSS certifications, with SDKs for Python, TypeScript, React, React Native, and Kotlin, plus an MCP server and support for bring-your-own LLM and voice.

  PricingHybrid · from $0.08 minute · free tier ✓

  TrustSOC 2 Type II · HIPAA · GDPR · ISO 27001 · PCI DSS

  Does

  • Outbound calling
  • BYO models
  • Multilingual

  Used byRevolut, Deliveroo, Epic Games, Deutsche Telekom

  Strengthstransparent public pricing · a free tier · self-serve signup

  ScoresAgent 65 · Pricing 100 · Setup 85 · Docs 55 · Procurement 100 · Trust 80

  ElevenLabs Conversational AI (ElevenAgents) profile →

• #2 OpenAI Realtime API (gpt-realtime)

  ███████░░░ 72 / 100

  OpenAI Realtime API is a WebSocket-based service for low-latency, bidirectional speech-to-speech communication, targeting developers building voice agents, real-time translation, live transcription, and call center automation. Pricing is usage-based starting at $0.0192 per minute of audio input, with self-serve signup and no sales call required. The API supports function calling, voice activity detection, interruption handling, and inbound SIP telephony via a third-party carrier. It holds SOC 2 Type II, HIPAA, GDPR, ISO 27001, and PCI DSS certifications, with SDKs available for Python, Node.js, Go, Java, Ruby, and .NET.

  PricingUsage · from $0.02 minute (audio input) · free tier ✗

  TrustSOC 2 Type II · HIPAA · GDPR · ISO 27001 · PCI DSS

  Does

  • Multilingual

  Used byPerplexity, Healthify, Speak, Zillow

  Strengthstransparent public pricing · self-serve signup · SOC 2 Type II

  Avoid ifYou want to try it free before paying

  ScoresAgent 50 · Pricing 85 · Setup 60 · Docs 50 · Procurement 85 · Trust 100

  OpenAI Realtime API (gpt-realtime) profile →

• #3 Telnyx Voice AI Agents

  ███████▓░░ 78 / 100

  Telnyx Voice AI Agents is a carrier-grade platform for building inbound and outbound voice AI, covering customer support automation, appointment scheduling, healthcare, and call center use cases across 45+ countries. Pricing is usage-based at $0.05 per minute with self-serve signup and no sales call required. The platform supports bring-your-own LLM and voice, function calling, SIP trunking, and SDKs for Node.js, Python, PHP, Java, Ruby, and Go. It holds SOC 2 Type II, HIPAA, GDPR, ISO 27001, and PCI DSS certifications, and customers include Dialpad, Alibaba, and Grupo Bimbo.

  PricingUsage · from $0.05 minute · free tier ✗

  TrustSOC 2 Type II · HIPAA · GDPR · ISO 27001 · PCI DSS

  Does

  • Built-in telephony
  • Outbound calling
  • BYO models
  • Multilingual

  Used byDialpad, Alibaba, AudioCodes, UJET

  Strengthstransparent public pricing · self-serve signup · SOC 2 Type II

  Avoid ifYou want to try it free before paying

  ScoresAgent 80 · Pricing 85 · Setup 60 · Docs 60 · Procurement 85 · Trust 100

  Telnyx Voice AI Agents profile →

• #4 Twilio ConversationRelay

  ███████▒░░ 76 / 100

  Twilio ConversationRelay is a WebSocket-based orchestration layer that handles speech recognition, text-to-speech, and real-time conversation flow for AI voice agents over PSTN, SIP, and WebRTC, supporting bring-your-own LLM and voice providers. It targets developers building inbound and outbound call automation, such as customer support, appointment scheduling, and live agent escalation. Pricing starts at $0.07 per minute for the orchestration layer, billed separately from underlying voice costs, with self-serve signup and SDKs for seven languages. The service reached general availability in May 2025 and holds SOC 2 Type II, HIPAA, GDPR, ISO 27001, and PCI DSS certifications, though HIPAA coverage requires a Security or Enterprise Edition account.

  PricingUsage · from $0.07 minute · free tier ✗

  TrustSOC 2 Type II · HIPAA · GDPR · ISO 27001 · PCI DSS

  Does

  • Built-in telephony
  • Outbound calling
  • BYO models
  • Multilingual

  Used byOhMD, Scorpion

  Strengthstransparent public pricing · self-serve signup · SOC 2 Type II

  Avoid ifYou want to try it free before paying

  ScoresAgent 55 · Pricing 85 · Setup 60 · Docs 70 · Procurement 85 · Trust 100

  Twilio ConversationRelay profile →

• #5 Vapi

  ███████▒░░ 75 / 100

  Vapi is a voice agent platform for building and deploying AI-powered phone agents handling inbound calls, outbound dialing, appointment scheduling, and lead qualification. Pricing is usage-based at $0.05 per minute with self-serve signup and no sales call required, plus an enterprise plan for custom concurrency. The REST API supports bring-your-own LLM and voice providers, ships SDKs for over ten languages and runtimes including mobile, and holds SOC 2 Type 2, HIPAA, GDPR, and PCI DSS certifications, with customers including New York Life and Intuit.

  PricingUsage · from $0.05 minute · free tier ✓

  TrustSOC 2 Type II · HIPAA · GDPR · PCI DSS

  Does

  • Built-in telephony
  • Outbound calling
  • BYO models
  • Multilingual

  Used byAmazon Ring, Kavak, Instawork, New York Life

  Strengthstransparent public pricing · a free tier · self-serve signup

  ScoresAgent 55 · Pricing 100 · Setup 85 · Docs 25 · Procurement 100 · Trust 85

  Vapi profile →

• #6 Cartesia Line

  ████████░░ 79 / 100

  Cartesia Line is a telephony platform for building and deploying AI voice agents, supporting inbound call handling, outbound calling, batch dialing, SIP trunking, and real-time conversation via a WebSocket API. It targets developers and businesses automating customer support or voice workflows, with customers including ServiceNow, Vapi, LiveKit, and Replicant. Pricing starts at $0.06 per minute with a free tier of 8 concurrent calls and 20,000 credits per month; enterprise plans are available. The platform holds SOC 2 Type 2, HIPAA, GDPR, and PCI DSS certifications, and ships SDKs for Python and JavaScript/TypeScript.

  PricingHybrid · from $0.06 minute · free tier ✓

  TrustSOC 2 Type II · HIPAA · GDPR · PCI DSS

  Does

  • Built-in telephony
  • Outbound calling
  • BYO models
  • No-code builder

  Used byServiceNow, Maven AGI, Retell, Vapi

  Strengthstransparent public pricing · a free tier · self-serve signup

  ScoresAgent 55 · Pricing 100 · Setup 85 · Docs 70 · Procurement 100 · Trust 65

  Cartesia Line profile →

• #7 Pipecat Cloud (Daily)

  ██████▒░░░ 64 / 100

  Pipecat Cloud is a managed hosting platform from Daily for deploying and scaling Pipecat voice AI agents in production, supporting inbound and outbound telephony via PSTN/SIP, WebRTC, and WhatsApp. It targets teams building customer support bots, IVR systems, and outbound call automation, with self-serve signup and usage-based pricing starting at $0.01 per minute. The platform spans four regions, offers Python and JavaScript SDKs with MCP server support, and holds SOC 2 Type 2, ISO 27001, HIPAA, and GDPR certifications. Notable users include NVIDIA, Descript, and Epic.

  PricingUsage · from $0.01 minute · free tier ✗

  TrustSOC 2 Type II · HIPAA · GDPR · ISO 27001

  Does

  • Built-in telephony
  • Outbound calling
  • BYO models

  Used byNVIDIA, Mercor, Descript, Epic

  Strengthstransparent public pricing · self-serve signup · SOC 2 Type II

  Avoid ifYou want to try it free before paying

  ScoresAgent 40 · Pricing 85 · Setup 60 · Docs 25 · Procurement 85 · Trust 90

  Pipecat Cloud (Daily) profile →

• #8 LiveKit Agents

  ███████░░░ 71 / 100
  • Cheapest to start

  LiveKit Agents is a developer platform for building and deploying realtime voice and video AI agents, supporting inbound and outbound telephony, SIP trunking, multi-agent orchestration, and bring-your-own LLM, STT, and TTS integrations. Pricing starts at $0.01 per minute with a free tier of 1,000 agent session minutes per month and no credit card required, scaling through tiered plans up to custom enterprise arrangements. SDKs are available for Python, Node.js, and Go, and the platform holds SOC 2 Type 2, HIPAA, and GDPR certifications, with HIPAA compliance restricted to Scale and Enterprise plans. Customers include OpenAI, Salesforce, Oracle, and Deutsche Telekom.

  PricingHybrid · from $0.01 minute · free tier ✓

  TrustSOC 2 Type II · HIPAA · GDPR

  Does

  • Built-in telephony
  • Outbound calling
  • BYO models
  • Self-hosted
  • No-code builder

  Used byOpenAI, Oracle, Salesforce, Deutsche Telekom

  Strengthstransparent public pricing · a free tier · self-serve signup

  ScoresAgent 55 · Pricing 100 · Setup 85 · Docs 30 · Procurement 100 · Trust 55

  LiveKit Agents profile →

See all 14 Realtime Voice Agent APIs compared →

How we rank

The headline score is the average of six 0-100 axes computed only from each API’s published, sourced fields: agent-friendliness, pricing transparency, setup speed, docs quality, procurement ease, and trust readiness. An unknown signal scores 0 for its axis - we credit what’s confirmed, never guess. The score is one input, not the verdict: we lead with each pick’s trade-off, and where a job has only one real option we say so rather than crown it. Full method on the methodology page.

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• ✓ Every field cited. Each profile links the source for every claim - check us.
• ✓ Public audit log. Every change to this data is recorded per field, with who changed it and why.
• ✓ Published, deterministic methodology. The score is a formula over the same fields you can see - recompute it yourself.
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• ✓ No reviews yet - and we say so rather than synthesizing them.

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