# Hume EVI vs OpenAI Realtime API

> Hume EVI vs OpenAI Realtime API: Hume EVI is our pick, leading for agencies and developers. They split on native integrations count and bring-your-own llm.

Both Voice AI platforms, Hume EVI (Emotionally intelligent speech-to-speech API (Empathic Voice Interface, EVI 3 / EVI 4 mini) with voice cloning and supplemental-LLM support.) and OpenAI Realtime API (Frontier speech-to-speech model API (gpt-realtime family) for low-latency voice agents over WebRTC, WebSocket, and SIP.) go head to head here. Start with the bottom line, then the verified fact table and real production costs.

Voice AI platforms · 18 facts compared · all sourced · pricing verified Jul 30, 2026

## Bottom line

Hume EVI wins four of six use cases outright, with the remaining two as ties and OpenAI Realtime API winning none. The wins rest on concrete advantages. For healthcare compliance, Hume EVI includes a HIPAA BAA on its base plan, a critical credential that OpenAI Realtime API does not match. For no-code agency deploys, Hume EVI offers a built-in no-code agent builder, which OpenAI Realtime API lacks. For custom pipeline control, Hume EVI supports bring-your-own LLM and bring-your-own TTS voice, while OpenAI Realtime API supports neither. Pricing starts at $0.07/min plus a $3/mo platform fee, with 11 languages supported and 300 ms median latency making it competitive on performance. OpenAI Realtime API offers native SIP trunking, but that single advantage was not enough to flip any use case.

## Verdict summary

| Use case | Winner | Why |
| --- | --- | --- |
| No-code agency deploys | Hume EVI | For a no-code agency deployment, the agent builder is the deciding factor. |
| Custom pipeline control | Hume EVI | For engineering teams building custom pipelines, the two most critical capabilities are bring-your-own LLM and full API-first control. |
| Ecommerce support and orders | Tie | For ecommerce support flows, the deciding factor is integrations that connect to commerce and CRM platforms. |
| Healthcare compliance | Hume EVI | For HIPAA-bound healthcare workflows, the single most critical requirement is a Business Associate Agreement, and Hume EVI includes a HIPAA BAA on its base plan. |
| Outbound sales campaigns | Tie | Neither tool has verified coverage of native outbound campaign management, concurrency limits, or warm transfer to human, which are the most critical factors for outbound sales campaigns. |
| SMB receptionist and booking | Hume EVI | For an SMB running a receptionist and booking service, keeping monthly costs low is the deciding factor. |

## Hume EVI vs OpenAI Realtime API: head-to-head facts

| Fact | Hume EVI | OpenAI Realtime API | Verified |
| --- | --- | --- | --- |
| Base price / min | $0.07 ([source](https://www.hume.ai/pricing)) | n/a | Jul 30 |
| HIPAA BAA on base plan | ✓  Included ([source](https://dev.hume.ai/docs/resources/privacy)) | n/a | Jul 30 |
| Native SIP trunking | n/a | ✓  Yes ([source](https://developers.openai.com/api/docs/guides/realtime-sip)) | Jul 30 |
| Median e2e latency | ~300 ms ([source](https://www.hume.ai/empathic-voice-interface)) | n/a | Jul 30 |
| Bring-your-own LLM | ✓  Yes ([source](https://dev.hume.ai/docs/speech-to-speech-evi/overview)) | ✗  No ([source](https://developers.openai.com/api/docs/guides/realtime)) | Jul 30 |
| Free tier credit | Free: 5 EVI min + 10k TTS chars/mo ([source](https://www.hume.ai/pricing)) | n/a | Jul 30 |

## Hume EVI vs OpenAI Realtime API pricing: true cost at 3 usage tiers

All-in monthly: platform fee + per-minute + telephony. Assumes GPT-4o class model, ElevenLabs voice.

| Volume | Buyer | Hume EVI | OpenAI Realtime API | Note |
| --- | --- | --- | --- | --- |
| 1K min/mo | Solo builder | $73 | n/a | Includes estimated telephony. Free credits can offset the first month. |
| 10K min/mo | Agency | $703 | n/a | Volume pricing typically starts to apply at this tier. |
| 100K min/mo | Call center | $7,003 | n/a | Both platforms offer custom contracts at this tier. Negotiate. |

## Hume EVI vs OpenAI Realtime API: verdicts by use case

### No-code agency deploys → Hume EVI

For a no-code agency deployment, the agent builder is the deciding factor. Hume EVI has a verified no-code builder while OpenAI Realtime API publishes none. Neither tool has published white-label or sub-account facts, so that attribute is a wash. On cost, Hume EVI charges $0.07/min plus a $3/mo platform fee, a concrete number agencies can budget against. OpenAI Realtime API bundles LLM and TTS costs into its pricing with no passthrough, making true per-minute costs harder to predict. Hume EVI's no-code builder is the clearest differentiator this use case demands.

### Custom pipeline control → Hume EVI

For engineering teams building custom pipelines, the two most critical capabilities are bring-your-own LLM and full API-first control. Hume EVI supports bring-your-own LLM while OpenAI Realtime API does not, locking teams into a single model. Both are fully API-first. Hume EVI also allows bring-your-own TTS voice, giving teams complete control over the audio stack, whereas OpenAI Realtime API does not. Hume EVI's vendor-claimed 300 ms median end-to-end latency is competitive. These two stack-control advantages are decisive for custom pipeline work.

### Ecommerce support and orders → Tie

For ecommerce support flows, the deciding factor is integrations that connect to commerce and CRM platforms. Hume EVI offers Claude, GPT, Gemini, plus bring-your-own LLM support and 5 SDKs, while OpenAI Realtime API provides WebRTC, WebSocket, SIP, MCP, and tool calling. Neither lists the specific ecommerce connectors (GHL, HubSpot, Zapier, Make, Twilio) that would tilt this category decisively. On platform fee, Hume EVI charges $3/mo versus no published platform fee for OpenAI Realtime API, a minor difference. Both offer self-serve signup. Without information on built-in knowledge base or DTMF/IVR for either tool, no meaningful separation exists on the remaining attributes.

### Healthcare compliance → Hume EVI

For HIPAA-bound healthcare workflows, the single most critical requirement is a Business Associate Agreement, and Hume EVI includes a HIPAA BAA on its base plan. No corresponding information shows that OpenAI Realtime API offers a HIPAA BAA at any tier, which is a decisive gap for any covered entity or business associate. Beyond compliance paperwork, Hume EVI also has verified consent and recording compliance tooling, directly addressing the audit and patient-consent obligations that healthcare teams face daily. OpenAI Realtime API has no corresponding information on either point. Both tools support barge-in, self-serve signup, and API-first development, so those factors do not differentiate here. Hume EVI's $0.07/min base rate with a modest $3/mo platform fee is also transparent and predictable.

### Outbound sales campaigns → Tie

Neither tool has verified coverage of native outbound campaign management, concurrency limits, or warm transfer to human, which are the most critical factors for outbound sales campaigns. On cost, Hume EVI runs $0.07/min versus OpenAI Realtime API pricing that is not directly comparable from the available information. OpenAI Realtime API has native SIP trunking, giving it a telephony edge, while Hume EVI supports bring-your-own LLM and voice for flexibility. Without data on these deciding factors, no winner can be named.

### SMB receptionist and booking → Hume EVI

For an SMB running a receptionist and booking service, keeping monthly costs low is the deciding factor. Hume EVI charges just $3 per month as a platform fee, while OpenAI Realtime API states no platform fee. Hume EVI also offers a no-code agent builder, which OpenAI Realtime API does not, making setup far more accessible for a small business without a dev team. Neither tool publishes information on built-in knowledge base or warm transfer, and neither supports buying or porting numbers in-platform. The no-code builder gives Hume EVI a meaningful practical edge for SMB operators.

## Hume EVI vs OpenAI Realtime API: common questions

### Is Hume EVI cheaper than OpenAI Realtime API?

The answer depends on your usage. Hume EVI charges $0.07/min plus a $3/mo platform fee, and its LLM and TTS costs are billed separately. OpenAI Realtime API bundles its model and audio costs into a single per-minute rate with no passthrough pricing. Because the total cost structures differ significantly, a direct cheaper-or-more-expensive comparison requires modeling your specific call volume and model choices.

### Hume EVI vs OpenAI Realtime API: which is better for no-code agency deploys?

Hume EVI is the stronger fit for no-code agency deploys. It includes a built-in no-code agent builder, supports bring-your-own LLM and bring-your-own TTS voice for client customization, and starts at $3/mo plus $0.07/min with a free tier. OpenAI Realtime API is strictly API-first with no no-code builder, no bring-your-own LLM option, and no bring-your-own voice support, making it better suited to developer-led builds.

### Does Hume EVI or OpenAI Realtime API support HIPAA compliance?

Hume EVI includes a HIPAA BAA on its base plan at no additional tier upgrade required. No information confirms that OpenAI Realtime API offers a HIPAA BAA, so healthcare teams with compliance requirements should factor that gap into their decision.

### Can I bring my own LLM or TTS voice to Hume EVI or OpenAI Realtime API?

Hume EVI supports both bring-your-own LLM and bring-your-own TTS voice. OpenAI Realtime API supports neither: you cannot swap in an external LLM or a custom TTS voice. If flexibility over your AI stack matters, Hume EVI is the more open option.

### Is Hume EVI or OpenAI Realtime API better for telephony and SIP-based call infrastructure?

OpenAI Realtime API offers native SIP trunking and supports WebRTC and WebSocket transport. Hume EVI has no confirmed native SIP trunking, though it does integrate with Twilio. Teams building on SIP infrastructure may find OpenAI Realtime API a more direct fit.

### Does Hume EVI have a free tier before I commit to paid usage?

Yes. Hume EVI offers a free monthly allowance of 5 EVI minutes plus 10,000 TTS characters, so you can prototype without immediately entering paid usage. A $3/mo platform fee applies once you move to a paid plan.

### What is Hume EVI's latency, and is it fast enough for real-time voice agents?

Hume EVI reports a vendor-claimed median end-to-end latency of 300 ms, which falls within the range typically considered acceptable for conversational voice applications. It also supports interruption handling (barge-in), which further reduces perceived lag in live conversations.

### How many languages does Hume EVI support?

Hume EVI supports 11 languages. Buyers targeting multilingual deployments should verify whether those 11 languages cover their required locales before committing.

### Do Hume EVI or OpenAI Realtime API require an annual contract to get their best pricing?

Neither tool requires an annual contract for best pricing. Both Hume EVI and OpenAI Realtime API offer their standard rates without locking you into a long-term commitment, which is useful for teams that need pricing flexibility early in a project.

### Does OpenAI Realtime API let me buy or port phone numbers inside the platform?

No. OpenAI Realtime API does not support buying or porting phone numbers in-platform. You would need to manage telephony through an external provider. However, OpenAI Realtime API does offer native SIP trunking as a connection path for those who bring their own carrier.

Source: https://www.versusref.com/voice-ai/hume-evi-vs-openai-realtime-api/