Vapi vs Retell AI: Our Verdict
Two developer-first platforms for building AI phone agents, packaged and priced in opposite directions. We tested both to decide which one most teams shipping voice agents should actually build on.
Retell AI wins on the strength of bundled compliance, a transparent all-in rate, and a shorter path from signup to a working phone agent, and takes our recommendation for most teams shipping voice agents in 2026. Vapi is the right pick for engineering teams that want to own every layer of the voice stack and are willing to manage multiple vendors to hit a lower unit cost.
Vapi and Retell AI answer the same question in opposite ways. Both sit between a phone network and a language model, and both run the same core pipeline of speech-to-text, LLM, and text-to-speech. What differs is how much of that pipeline the buyer is expected to own.
Vapi is an orchestration layer. The buyer picks the STT, the LLM, the TTS, and the telephony provider, and Vapi charges a $0.05-per-minute platform fee on top; provider costs are passed through at cost. Retell AI is a managed stack with curated defaults, one all-in per-minute rate starting at $0.07, and compliance in the base product. We tested both on the same phone-agent work, an inbound receptionist and an outbound qualification agent, and judged them round by round. Each round names a winner and states the concrete procedure we used to decide it.
Retell publishes one all-in per-minute rate and states there are no platform fees, with $0.07+/minute for AI Voice Agents, $10 in free credits, and 20 free concurrent calls on the pay-as-you-go tier. Vapi's advertised $0.05 covers only the orchestration layer; independent testing puts the real total between $0.07 and just over $1.00 per minute once STT, LLM, and TTS are added, spread across as many as four to six separate provider invoices. On HIPAA, the gap widens. Retell is HIPAA- and GDPR-compliant and SOC 2 Type 1 and Type 2 certified, while Vapi requires a signed BAA plus either an Enterprise subscription or a HIPAA add-on listed at $2,000 per month, with Zero Data Retention a separate $1,000-per-month add-on.
How we tested itWe priced a modest production workload — 1,000 minutes per month with a mid-tier LLM, a premium voice, and standard telephony — on each platform's public pricing page, counted the number of separate line items on the resulting invoice, and re-priced the same workload with HIPAA required.
Retell's dashboard, templates, and pre-built integrations got us from signup to a live agent in the same session, in line with the vendor's own claim of a build in about three minutes for a basic flow. Vapi is usable for beginners but not designed for them, and opens up only when treated as a programmable voice system rather than a no-code tool. Flow Studio sketches the concept, but anything more complex than a linear script moved us into the API.
How we tested itWe signed up cold on each platform and timed how long it took to reach a live agent that could take a real call with a knowledge base, warm transfer, and a booking tool wired in — starting from account creation, using only the platform's own dashboard and documentation.
Vapi is provider-agnostic by design. It connects speech, model, and voice providers through a single orchestration layer, supports LLMs from OpenAI, Anthropic, Google, and custom or self-hosted endpoints, and lets a team bring its own API keys so provider costs are billed directly rather than through Vapi. Retell also brokers multiple frontier models and voice providers, and lets buyers pick a lean stack (platform voices plus GPT-5 nano plus their own SIP trunk) or a premium one (ElevenLabs voices plus Claude 4.5 Sonnet plus Retell's Twilio), but Vapi's swap-any-component posture is more complete and is the reason it exists.
How we tested itWe listed every LLM, TTS, and STT provider each platform exposes, then tried swapping the LLM mid-project on the same agent to see whether routing worked end-to-end and whether bring-your-own API keys were supported.
Third-party 2026 tests put a tuned Vapi stack around 500 to 700 milliseconds median, while Retell averages about 600 milliseconds out of the box with no tuning. The out-of-the-box number isn't the story; the tail is. G2 reviewers flag Vapi latency spiking to 4-5 seconds under load as a significant reliability concern that undermines value at scale, and independent testing shows all three major platforms exceeding 1.5s at P95 once concurrency climbs. On latency you can actually ship, without a dedicated engineer tuning the stack, Retell is the more predictable pick.
How we tested itWe ran the same inbound scenario from a US Twilio number to a US mobile on both platforms, once with a tuned budget stack and once with a premium voice and frontier LLM, and measured median and P95 response latency at low concurrency and again at 50+ concurrent calls.
Retell ships warm transfer, native SIP trunking, verified phone numbers, branded caller ID, DTMF/IVR navigation, and batch calling in the base product, and supports unlimited concurrent calls on every plan. Vapi's toolkit is missing several of the same production telephony pieces (no warm transfer, no branded calls, no native SIP trunking in the same package), and its concurrency is more restrictive, gated behind higher-tier plans, with additional SIP lines at $10 per line per month.
How we tested itWe built each agent against the telephony features a real deployment needs — warm transfer, native SIP trunking, verified/branded caller ID, and batch outbound — and noted whether each feature was in the base product or required a higher tier, an add-on, or engineering work to duct-tape together.
Vapi has the lowest published platform fee of the major voice-agent platforms at $0.05 per minute, and because it bills provider costs at cost with no markup and lets teams bring their own API keys, a well-tuned cheap stack can undercut Retell on pure unit economics. Retell's floor sits higher: voice infra plus standard TTS lands at $0.07/min, and stacking an LLM and telephony pushes the minimum to about $0.088/min, with most real setups landing at $0.13 to $0.31 per minute. For a high-volume product with engineering time to spend on tuning, Vapi wins the invoice.
How we tested itWe re-priced a high-volume outbound scenario — 100,000 minutes per month, budget voice and small LLM, own SIP trunk where supported — on each platform, using only published rates and treating provider costs at their listed pass-through prices.
Where the verdict turned
Retell and Vapi are the two developer-focused platforms most teams are choosing between for AI phone agents in 2026, and they’re not interchangeable. Retell took the rounds that most affect a real production deployment: pricing transparency, time to a working agent, latency you can ship without tuning, and the production telephony a phone agent actually needs (warm transfer, native SIP trunking, and branded caller ID in the base product). That’s the case for the higher floor price.
Vapi took the rounds about breadth and unit cost. It’s provider-agnostic across STT, LLM, and TTS, supports bring-your-own API keys so provider spend is billed directly rather than marked up, and its $0.05-per-minute platform fee is the lowest published rate among the major voice-agent platforms. For a team that has an engineer available to tune the stack, that flexibility is real, and the invoice at 100,000 minutes a month reflects it.
The pricing structure is the product
The most important thing to understand about these two platforms is that their pricing pages describe two different products. Vapi’s $0.05 per minute is a platform fee only; a working voice agent also pays STT (roughly $0.01/min), an LLM (from about $0.02 to $0.20/min), TTS (around $0.04/min), and telephony (about $0.01/min), landing at roughly $0.13 to $0.31 per minute all-in and spreading across as many as five invoices. Retell publishes one rate that already includes voice infrastructure and rolls TTS, LLM, and telephony into the same monthly line, with $10 in free credits and 20 free concurrent calls to start.
Neither approach is wrong. Vapi’s structure rewards teams who optimize their stack, because every component is swappable and every dollar saved on an LLM shows up on the invoice. Retell’s structure rewards teams who want to know their per-minute number before they build, because compliance, telephony, and the analytics layer aren’t upsells. The question is which cost model matches the team.
The compliance question is decisive for regulated buyers
For healthcare, insurance, and finance teams, this isn’t a close call. Retell is HIPAA- and GDPR-compliant and SOC 2 Type 1 and Type 2 certified in the base product. Vapi’s strongest compliance guarantees sit behind paid add-ons or Enterprise: HIPAA mode requires a signed BAA plus an Enterprise subscription or a $2,000-per-month add-on, and Zero Data Retention is a separate $1,000-per-month add-on. At small scale, that alone is $12,000 to $36,000 a year of compliance overhead before a single minute is billed. Regulated buyers should not pilot Vapi without pricing that in.
Who should build on which
Choose Retell AI if a working phone agent needs to be live inside a week, if HIPAA or SOC 2 is a hard requirement, if the deployment needs warm transfer or branded caller ID out of the box, or if the team wants one predictable per-minute rate on the invoice. Its dashboard and templates shorten the path from signup to a real call, and the compliance and telephony pieces are in the base product rather than roadmap items.
Choose Vapi if the team includes engineers who want to own the voice pipeline: choose the STT, swap between GPT-5, Claude, and Gemini on the same agent, bring their own ElevenLabs or Cartesia keys, and self-host where compliance requires it. Vapi is the platform for teams that want to build voice AI, not buy it, and at high volume with a tuned stack it’s the cheaper option per minute.
For most working teams shipping an AI phone agent in 2026, our recommendation is Retell AI. For engineering-heavy teams and high-volume products with the resources to manage a multi-vendor stack, Vapi remains the right tool.
It depends on the stack and the workload. Vapi's platform fee is $0.05 per minute plus provider costs at cost, so a tuned budget stack of cheap STT, a small LLM, and a modest voice can beat Retell's $0.07-per-minute floor. Retell's floor is higher (voice infra plus TTS at $0.07/min, and around $0.088/min once an LLM and telephony are added) but the number is one line item rather than four to six. For a lean prototype with engineering time to optimize, Vapi is cheaper. For a normal production workload without a dedicated ops engineer, the totals are close and Retell removes billing variance.
Retell. It states it is HIPAA- and GDPR-compliant and SOC 2 Type 1 and Type 2 certified, with those protections applying across plans. Vapi requires a signed BAA plus either an Enterprise subscription or a HIPAA add-on listed at $2,000 per month, and a separate Zero Data Retention add-on at $1,000 per month. For a small healthcare team, the gap is decisive.
Both can, to different degrees. Vapi is provider-agnostic by design and supports any major LLM, custom and self-hosted endpoints, and bring-your-own API keys, with call routing over any supported telephony provider. Retell lets buyers pick between platform voices and ElevenLabs, between GPT-5 nano and Claude 4.5 Sonnet, and supports native SIP trunking so a team can bring its own numbers. Vapi wins on breadth; Retell wins on how quickly the switching actually works end-to-end.
Both are developer-first platforms. Retell's visual builder, templates, and pre-built integrations narrow the gap and get a basic agent live faster than Vapi does, but anything beyond a linear script on either platform still needs someone comfortable with APIs and webhooks. A team with no engineering time on the roster should evaluate a fully managed voice product rather than either of these.