Retell AI vs VAPI: Which Voice Agent Platform Should You Actually Build On?

You've narrowed it down to two platforms for your voice AI build: Retell AI and VAPI. Both handle inbound and outbound phone calls. Both support the major LLMs. Both let you deploy AI agents that answer the phone for your business. So which one do you actually choose?

I've deployed voice agents on both. The Retell AI vs VAPI decision isn't about which is "better" in some abstract sense. It's about which one matches your team, your clients, and your use case. And most comparison posts get this wrong because they stop at the feature list.

Here's the breakdown with real 2026 pricing numbers and a decision framework that will point you to the right platform in under five minutes.

Quick Verdict

• Pick Retell AI if you want faster time to value, bundled pricing you can predict, or you're building for healthcare or enterprise clients who need SOC2 and HIPAA out of the box.
• Pick VAPI if you're developer-heavy, need to swap LLMs or TTS providers freely, are building multi-agent workflows with their Squads feature, or want to optimize costs at high volume by controlling every component.
• Still deciding? Book a 15-minute call. I've deployed both in production and can tell you which fits your specific build in under 10 minutes.

Key Takeaways

• Retell AI uses bundled all-in pricing ($0.07-$0.31/min). VAPI charges $0.05/min orchestration plus provider pass-through, putting real all-in cost at $0.10-$0.20/min.
• Retell AI includes 20 free concurrent calls. VAPI includes 10.
• HIPAA: Retell offers BAA on Enterprise. VAPI charges $1,000/month for HIPAA Zero Data Retention regardless of plan size.
• VAPI's Squads feature (launched November 2025) enables true multi-agent handoffs. Retell has a no-code flow builder but not the same multi-agent architecture.
• For agencies shipping to non-technical clients: Retell. For developer teams wanting full stack control: VAPI.

What We're Actually Comparing

Both Retell AI and VAPI are voice AI orchestration layers. They sit between your business logic and the raw call infrastructure, handling the phone connection, streaming audio to speech-to-text, routing text to an LLM, converting the LLM response back to audio, and returning that audio to the caller in real time.

Neither platform is a finished product. You still write the system prompt, connect your integrations (CRM, calendar, payment processor), and define what happens in edge cases. The platform handles the hard real-time audio engineering.

Where they diverge is philosophy. Retell AI takes an opinionated, managed approach: they bundle voice infrastructure, LLM routing, and turn-taking into one offering. VAPI takes an open, modular approach: you pick every component, they orchestrate. That single difference drives every tradeoff in this post.

Retell AI's platform homepage, positioning their managed voice orchestration layer for businesses and developers alike.

Retell AI: The Managed Voice Platform

Retell AI launched out of Y Combinator and has grown to 3,000+ businesses. G2 rates them 4.8 out of 5 from 929 reviews and named them "Best Agentic AI Software" in 2026. At 929 reviews that's a real signal, not a launch week bump.

The platform's core pitch is managed simplicity. You bring a system prompt and your integrations. Retell handles the voice infrastructure, LLM routing, turn-taking, and orchestration. Their proprietary voice layer, including a custom ASR model upgraded in late 2025, is what separates them from platforms that just wire together commodity providers.

Retell AI Pricing (April 2026)

Retell uses all-in per-minute pricing. The Pay As You Go tier starts at roughly $0.07/min for the simplest configuration (Retell Voice Infra plus their cheapest TTS plus GPT-4.1 Nano) and goes up to around $0.31/min if you run ElevenLabs voices with GPT-5.4. Billing is tracked to the nearest second with no per-call rounding. The $10 signup credit covers your first several hundred test calls.

Here's how the components stack:

• Retell Voice Infra (base): $0.055/min on every call

• TTS: $0.015/min (Retell Platform, Cartesia, Minimax, Fish, OpenAI) or $0.040/min (ElevenLabs)

• LLM: $0.004/min (GPT-4.1 Nano) to $0.160/min (GPT-5.4 Fast Tier)

• Telephony via Twilio (US): $0.015/min; free if you bring your own SIP

• Phone numbers: $2/month each

• First 20 concurrent calls included; additional at $8/slot/month

• Knowledge Base: $8/KB/month (first 10 free)

One thing that catches people off-guard: billing continues during silence. If a caller puts you on hold, the STT stays active and you keep paying. At average call lengths that's negligible. For workflows with long hold sequences, it adds up.

Retell AI's pricing page showing the component-level breakdown for Pay As You Go and the Enterprise tier.

What Retell AI Does Well

• No-code flow builder: drag-and-drop agentic conversation flows, no backend engineering required for branching logic

• Latency: approximately 600ms end-to-end with a proprietary turn-taking model that handles natural interruptions

• Compliance: SOC2 Type II certified, HIPAA BAA available on Enterprise

• Simulation testing: run test calls against your agent before going live, catching edge cases before real callers do

• AI Quality Assurance: post-call analysis at $0.10/min (first 100 minutes free) for continuous monitoring

• Batch calling: outbound campaigns with conversion tracking and a $0.005/dial add-on

• Verified Phone Numbers: spam prevention for outbound at $10/number/month

• AI Chat Agents: separate product at $0.002/message for non-voice use cases

Where Retell AI Has Limits

ElevenLabs voices cost 2.67x more than Retell's other TTS options ($0.040 vs $0.015/min). If you want the most polished-sounding voice, you're paying a meaningful premium at scale. And while custom LLM endpoints are supported, getting there requires engineering work that bypasses the no-code flow builder's appeal. The Enterprise On-Prem option (deploy within your own infrastructure) is now listed, but custom configurations like that mean you're beyond the self-serve path.

VAPI: The Developer-First Voice API

VAPI positions itself as the AWS of voice AI: powerful primitives, maximum configurability, and you bring the expertise to assemble them. Their tagline targets developers directly: "Build, test, and deploy advanced voice AI agents in minutes with Vapi." For engineers, that's genuinely true. For teams without backend developers, it's a more involved process than the tagline suggests.

They shipped fast in 2025 and 2026. Squads (multi-agent handoffs) in November 2025. Structured outputs from calls in November 2025. Vapi Voices (native TTS for lower cost and latency) in December 2025. A testing framework in December 2025. Vapi Monitoring (call analytics and observability) on April 15, 2026. Enhanced Security Mode on April 1, 2026. That's a platform in active development, which is good and occasionally fiddly when things shift under you.

VAPI's homepage positioning them as the developer-first voice AI platform with full provider flexibility.

VAPI Pricing (April 2026)

VAPI's number is $0.05/min, but that's only their orchestration fee. Real all-in cost adds STT, LLM, and TTS at each provider's pass-through rate. A realistic all-in estimate: $0.10-$0.20/min depending on what you configure.

Or with Vapi Voices (their native TTS launched December 2025 at lower cost and latency) plus Deepgram: your all-in cost drops below that estimate. At scale, teams that optimize their VAPI stack this way can undercut Retell's equivalent configuration. But you need to know what you're optimizing.

HIPAA compliance on VAPI requires a $1,000/month Zero Data Retention add-on regardless of your plan size. For a 3-person healthcare startup, that's significant before you've proven the product. Concurrent lines: 10 on Pay As You Go, then $10/line/month. Enterprise pricing is custom and bundles provider costs.

What VAPI Does Well

• Provider flexibility: swap any LLM, STT, or TTS provider independently. GPT-5, Claude, Gemini, Llama, Mistral, DeepSeek, or your own custom endpoint

• Squads: multiple AI assistants that can hand off to each other within a single call. Triage agent routes to booking agent routes to billing agent, all AI, no human transfers

• Developer tooling: CLI, MCP server (integrates VAPI into AI coding tools), automated testing framework, Vapi Monitoring observability dashboard

• Latency: sub-500ms target with documented engineering investment in optimization

• Structured outputs: extract validated, typed data from calls (November 2025)

• Composer: visual workflow builder for teams that don't want to hand-code every flow

• Cost optimization path: Vapi Voices plus a cost-efficient LLM is the route to lowest per-minute costs at high volume

Where VAPI Has Limits

The $0.05/min headline is the most misleading number in this space right now. It looks cheaper than Retell until you realize you're assembling your own stack and each component adds to the bill separately. For a team without backend engineers, managing three vendor relationships for one call is a real operational burden.

Call history on Pay As You Go persists only 14 days. For regulated industries that need call records, that's a compliance issue. And the $1,000/month HIPAA add-on means VAPI's healthcare story is essentially enterprise-only from a compliance standpoint. The legacy Startup/Agency plan was eliminated and customers were migrated. That's worth noting as a signal about pricing stability.

Retell AI vs VAPI: Head-to-Head Comparison

VAPI's pricing page. The $0.05/min is VAPI's fee only. Add your STT, LLM, and TTS provider costs on top.

6 Questions That Point You to the Right Platform

Answer these honestly. They'll tell you more than any feature list.

1. Does your team have a dedicated backend engineer? If yes: VAPI. If no: Retell AI. The VAPI advantage is meaningless if nobody on your team can assemble and maintain a multi-provider stack.

2. Are you building for healthcare clients right now? If yes and you're not at enterprise volume: Retell AI. VAPI's $1,000/month HIPAA add-on is expensive before you've proven the product. Retell's HIPAA BAA comes via Enterprise contract which requires a sales conversation, but that's the better path for most healthcare deployments.

3. Do you need multi-agent orchestration? Multiple AI agents handing off to each other within a single call flow? VAPI's Squads is purpose-built for this. Retell's flow builder handles branching well, but it's not the same architecture as true multi-agent handoffs.

4. Will you need to swap LLMs frequently? Testing GPT-5 against Claude 4.6 Sonnet against Gemini Flash for cost and quality on your specific use case? VAPI's provider-agnostic architecture makes this a config change. Retell supports the same LLMs, but VAPI's pass-through pricing gives you cleaner cost visibility per provider.

5. Do you need predictable monthly billing? Retell's bundled model is easier to forecast. You know roughly what each minute costs before you write the system prompt. VAPI's add-up-the-components model is more flexible but harder to predict until you've settled on a stack and measured it.

6. Are you an agency shipping agents for SMB clients? If you're deploying 5 to 20 voice agents per month for non-technical clients, Retell's no-code flow builder, simulation testing, AI QA, and Branded Call ID will save you hours per deployment. VAPI's Composer is catching up, but Retell's deployment workflow is more polished for client handoffs right now.

What Most Comparisons Get Wrong About This Decision

Every other Retell AI vs VAPI post compares feature lists and calls it analysis. But the real question isn't which platform has more capabilities. It's which platform matches what your team can actually operate.

VAPI has more configuration options. But that's also a liability when you don't have the bandwidth to manage a five-vendor call pipeline. Provider outages, API version changes, TTS voice degradation between model versions. Those are real operational events when you're assembling your own stack. On Retell, their team is responsible for the orchestration layer working. On VAPI, you are.

I've watched teams pick VAPI because the headline pricing looked lower, then spend three weeks integrating providers and chasing a latency issue that turned out to be a Deepgram region routing problem. And I've watched teams pick Retell for simplicity, then hit a wall when they needed a custom LLM endpoint that required engineering work anyway.

The best platform is the one your team will actually maintain six months after the initial deploy. Not the one with the most features on launch day.

A Real Deployment: What This Looks Like in Practice

A 14-seat US law firm doing plaintiff personal injury intake came to me needing a voice agent to handle after-hours calls, qualify leads against their intake criteria, and book consultations directly in their calendar. They had no technical staff. A paralegal handled their tech issues. I used Retell AI.

Setup took about four hours: system prompt for intake qualification, Cal.com integration for booking, Retell's Twilio telephony for the phone number. The flow builder let me map the full conversation tree: opening, injury type, statute of limitations, insurance status, then booking or warm transfer if qualified. Simulation testing let me run 40 test calls before going live. We caught 7 edge cases in simulation that would have been embarrassing on real prospect calls.

The agent handled 189 calls in month one. 71 were qualified leads. 43 booked consultations. Cost: about $58 in Retell usage for the month, roughly $0.31/min because I used ElevenLabs for a polished voice. They closed 6 new cases that month. The retainer paid for itself inside week two.

For a different project, a SaaS company building a white-label voice AI platform where each of their customers could configure their own LLM and TTS, I would have used VAPI. That multi-tenant, bring-your-own-model architecture is exactly what VAPI was designed for. That's the real answer to the Retell AI vs VAPI question. They're both solid. They're just built for different situations.

You can read more production deployments in my case studies and see how the right platform choice played out across different industries.

If You've Decided You Need a Custom Voice Agent Built

Both platforms are tools. Someone still has to build the agent, write the system prompt, handle the integrations, test the edge cases, and maintain it when production gets weird. That's where I come in.

I've built voice agents and AI automation systems across law, healthcare, real estate, HVAC, and ecommerce, and I've been doing it for long enough to know which platform will save you headaches on which client type. For context on the full range of what voice AI costs, the AI voice agent pricing breakdown covers what you should budget across build options.

The Revenue Capture System ($5,000 to $7,500 plus $500 to $800/month) is where most voice agent projects land. That's a production agent handling your inbound calls, qualified and integrated with your calendar or CRM, with a 60-day support retainer. If you're earlier in the process and want to map the right architecture before committing, the AI Revenue Blueprint ($1,500 to $2,500) gets you that plan in two weeks.

Not sure if you need a voice agent at all? The AI readiness assessment will tell you whether this is the right first system for your business. And if you want a direct comparison of AI answering services versus human receptionists before deciding on a platform at all, the AI vs human answering service breakdown is the place to start.

FAQ

Is Retell AI or VAPI cheaper?

It depends on your stack. Retell's all-in pricing runs $0.07 to $0.31/min depending on LLM and TTS choices. VAPI's orchestration is $0.05/min, but adding STT, LLM, and TTS pass-through puts real all-in cost at $0.10 to $0.20/min typically. With Vapi Voices and a cost-efficient LLM at high volume, VAPI can undercut Retell. For most configurations using ElevenLabs voices the costs are comparable.

Which has lower latency, Retell AI or VAPI?

VAPI targets sub-500ms end-to-end. Retell claims approximately 600ms. In practice, latency depends heavily on your LLM choice regardless of platform. A slower LLM adds delay on both. VAPI has published detailed technical documentation on their latency optimizations. Retell's proprietary turn-taking model handles natural conversation interruptions well even at slightly higher latency.

Does Retell AI support HIPAA compliance?

Yes, via BAA on the Enterprise plan. VAPI also supports HIPAA but charges $1,000/month for their Zero Data Retention add-on at any plan level. For small healthcare practices or early-stage healthcare startups, Retell's enterprise path may actually be more accessible for total cost, though it does require a sales conversation rather than self-serve signup.

Can I use my own LLM with Retell AI or VAPI?

Both support custom LLM endpoints. You bring your own model by pointing the platform at your API. Retell supports this on Pay As You Go. VAPI makes it a core architectural feature. For VAPI, the custom LLM is just another swappable component in the same way you swap TTS providers.

How many concurrent calls can each platform handle?

Retell AI includes 20 concurrent calls on Pay As You Go at $8/slot/month for additional capacity. VAPI includes 10 concurrent lines at $10/line/month for additions. For high-volume outbound campaigns, Retell's 20 free slots give more headroom before additional costs kick in.

Which platform is better for agencies building voice agents for clients?

Retell AI. The no-code flow builder, simulation testing, AI Quality Assurance, and Branded Call ID add-on are all purpose-built for agencies deploying agents to SMB clients. VAPI's Composer is closing the gap, but Retell's deployment workflow is more polished for non-technical client handoffs right now.

What is VAPI Squads and how does it work?

Squads let you define multiple AI assistants that can hand off to each other during a single call. Example: a triage assistant gathers initial information, transfers to a booking specialist, then escalates to a billing agent if needed. All AI, no human transfers. Launched November 2025, this is one of VAPI's clearest technical advantages for complex multi-step workflows where Retell's flow builder reaches its limits.

Can I use Retell AI or VAPI for outbound calling campaigns?

Both platforms support outbound calling. Retell's Batch Call feature runs outbound campaigns with conversion tracking and a $0.005/dial add-on. VAPI launched outbound call campaigns in June 2025. Both let you trigger calls via API with contact lists. Retell's Branded Call ID ($0.10/outbound call) and Verified Phone Numbers ($10/number/month) add-ons improve answer rates on outbound calls significantly.

Citation Capsule: Retell AI pricing, features, and case study data from retellai.com/pricing (April 2026). VAPI pricing and feature data from vapi.ai/pricing and docs.vapi.ai (April 2026). Retell AI G2 rating (4.8/5 from 929 reviews) from G2.com. VAPI Monitoring launch and Enhanced Security Mode announcements from vapi.ai/blog (April 2026). Retell AI case studies (Pine Park Health, SWTCH, Medical Data Systems) from retellai.com/customers.