Voice AI Platforms Compared 2026: Ortavox vs Vapi vs Retell vs Bland AI vs ElevenLabs Agents
An updated, comprehensive comparison of the leading voice AI platforms in 2026. Latency benchmarks, pricing models, TTS/LLM/STT support, compliance, and developer experience — everything you need to choose the right platform.
The voice AI infrastructure market has matured significantly in 2026. Five platforms now dominate developer mindshare: Ortavox, Vapi, Retell AI, Bland AI, and ElevenLabs Agents (launched Q4 2025). This guide gives you an honest, up-to-date comparison across every dimension that matters.
Disclosure: This comparison is written by the Ortavox team. We have done our best to represent competitors accurately based on their public documentation and pricing as of March 2026. Contact us if you spot anything outdated.
Quick comparison matrix
| Ortavox | Vapi | Retell AI | Bland AI | ElevenLabs Agents | |
|---|---|---|---|---|---|
| Latency p50 | ~540ms | ~720ms | ~650ms | ~700ms | ~600ms |
| Free tier | 100 min/mo forever | Trial credits | Trial credits | No | Trial credits |
| Base pricing | $0.055/min + providers | $0.05/min + markup | $0.07/min + markup | ~$0.09/min all-in | $0.05/min + EL costs |
| BYOK (LLM) | Yes | Yes | Yes | Partial | No (EL LLM only) |
| BYOK (STT) | Yes | Yes | Yes | No | EL Scribe only |
| BYOK (TTS) | Yes | Yes | Yes | No | ElevenLabs only |
| SOC 2 Type II | Yes | Yes | Yes | In progress | Yes |
| HIPAA BAA | Enterprise | Enterprise | Enterprise | No | Enterprise |
| Interruption handling | < 300ms | ~400ms | ~350ms | ~600ms | ~350ms |
| Custom voices | Any provider | Any provider | Any provider | Limited | ElevenLabs only |
| Telephony | Twilio/SIP/PSTN | Twilio/SIP | Twilio/SIP | Own numbers | Twilio |
| Function calling | Yes (JSON schema) | Yes | Yes | Yes | Yes (EL tools) |
| Open source SDK | Yes | Yes | Yes | No | Partial |
| Monthly changelog | Yes | Yes | No | No | Yes |
Latency: who is actually fastest?
Latency is measured end-to-end: from the moment the user stops speaking to the moment the first audio byte reaches the caller. All figures below are p50 (median), using GPT-4o-mini + Deepgram Nova-2 + Cartesia Sonic as the baseline stack on each platform.
Ortavox achieves ~540ms p50 through parallel pipeline processing: edge VAD with no silence timeout, streaming STT-to-LLM overlap, and sentence-boundary TTS triggering. Retell and ElevenLabs Agents are the next fastest at ~600–650ms. Vapi and Bland AI are slower primarily because they use silence-timeout VAD by default.
All platforms improve latency significantly when you swap GPT-4o for Groq Llama 3.1-70B. Groq's median TTFT is ~80ms vs. ~250ms for GPT-4o. If latency is your top priority, use Groq.
Pricing: the real all-in cost
Platform pricing is only part of the story. Voice AI calls incur costs from four sources: the platform fee, STT transcription, LLM inference, and TTS synthesis. Platforms that bundle these into a single per-minute rate are simpler but more expensive if you use cost-efficient models.
Example: a 5-minute call using GPT-4o-mini (500 tokens in/out), Deepgram Nova-2 ($0.0043/min), and Cartesia Sonic ($0.015/1K chars, ~800 chars/min):
| Platform | Platform fee | STT | LLM | TTS | Total for 5 min |
|---|---|---|---|---|---|
| Ortavox | $0.28 | $0.022 | $0.015 | $0.06 | ~$0.38 |
| Vapi | $0.25 | $0.025 | $0.018 | $0.07 | ~$0.36 |
| Retell AI | $0.35 | $0.025 | $0.018 | $0.07 | ~$0.46 |
| Bland AI | $0.45 (all-in) | included | included | included | ~$0.45 |
| ElevenLabs Agents | $0.25 | EL Scribe ($0.04) | $0.02 | EL ($0.09) | ~$0.40 |
Vapi and Ortavox come out closest on cost for this stack. Retell is ~20% more expensive. Bland AI is competitive but you lose model choice. ElevenLabs Agents is most expensive on TTS if you're using their premium voices — but cheapest if you use their free tier voices.
Provider flexibility: why BYOK matters
Bring Your Own Key (BYOK) lets you use your own API keys for LLM, STT, and TTS. This matters for three reasons: your negotiated rates (at scale, OpenAI enterprise pricing is significantly lower), data agreements (your key means your data processing terms apply), and model access (fine-tuned or private models).
Ortavox, Vapi, and Retell all support full BYOK across all three provider types. Bland AI supports LLM BYOK but uses its own STT/TTS stack. ElevenLabs Agents is locked to ElevenLabs Scribe for STT and ElevenLabs voices for TTS — a significant lock-in if you want to use Deepgram or Cartesia.
Developer experience
Vapi has the strongest developer community, the most integrations, and the most tutorial content. Their CLI, dashboard, and monthly changelog posts make it the easiest platform to evaluate quickly. Retell has a clean dashboard but shallower documentation. Bland AI is the simplest to use but the least extensible. ElevenLabs Agents benefits from ElevenLabs' existing Studio UI but is the newest platform of the five.
Ortavox prioritizes low-level control: full WebSocket API access, configurable VAD parameters, and support for custom OpenAI-compatible LLM endpoints. If you need to tune the pipeline yourself or run custom infrastructure, Ortavox gives you the most knobs.
Which platform should you choose?
- •Ortavox — best for: lowest latency, full provider choice (including Voxtral TTS, any LLM endpoint), transparent pricing, HIPAA workloads.
- •Vapi — best for: largest community, most third-party integrations, excellent documentation, easiest onboarding.
- •Retell AI — best for: polished UI, solid mid-tier feature set, good compliance documentation.
- •Bland AI — best for: fully managed experience with built-in phone numbers, no infrastructure management.
- •ElevenLabs Agents — best for: teams already using ElevenLabs voices who want native conversational AI without switching TTS providers.