SAME CATEGORY. YOUR PRIORITIES.
Retell AI vs Vapi
Compare evidence, costs and trade-offs. Adjust the criteria to reflect your own workflow.
MAKE THE SCORE YOURS
What matters most?
Core capabilities carry 32 points; workflow depth carries 68. AI contributes the category-specific weight shown below within those totals. Change group priorities and see every contribution update.
How the score is calculated →Documented fit across available plans · unknowns shown as ranges · no customer ratings
| Features & decision context |  Retell AI80–99/100 documented fit Core capabilities32 / 32 pts10/10 checks with established status Workflow depth47.9–66.8 / 68 pts12/18 checks with established status |  Vapi71–100/100 documented fit Core capabilities32 / 32 pts10/10 checks with established status Workflow depth38.6–68 / 68 pts8/18 checks with established status |
|---|---|---|
| How AI changes fitSame priorities, with and without AI | 80–99 with AI80–100 without AIFeature-fit points; not measured ROI | 71–100 with AI76–100 without AIFeature-fit points; not measured ROI |
| Supplier website | Visit Retell AI | Visit Vapi |
| Good fit for | Teams building production phone agents who want a packaged voice stack and measurable testing workflow. | Engineering teams that want to control models, tools, deployment and application behavior. |
| Look more closely when | You plan to budget from the lowest advertised minute rate without model, voice, telephony and add-ons. | You expect the $0.05 hosting rate to include every model, speech and carrier cost. |
| Pricing snapshotDifferent billing units are not directly comparable | Usage basedper configured conversation minute Published AI voice range is $0.07–$0.31/minute, depending on configuration. Telephony and selected add-ons are additional; the full model/voice menu can exceed the headline range. Pricing source | $0.05per minute hosting only Build has $0 platform subscription and $0.05/minute Vapi hosting; speech, language-model and telephony provider charges are separate. Pricing source |
| Phone and web voice deployment 20% base weight | ||
| Core capabilityTelephone deploymentDeploy an agent to a documented phone or voice-calling channel. | Supported4 / 4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported4 / 4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
| Core capabilityWeb voice or SIP connectionDeploy voice through a browser interface or connect telephony using SIP. | Supported4 / 4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported4 / 4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
Depth checkConfigured live-call transferConfigure a production call transfer to a person or destination with observable transfer behavior.Ask for a demonstrationMake a test phone call and transfer it to the configured human destination. A scenario to run with the supplier; not a completed product test. | Supported5.6 / 5.6 pts Transfer tools support human warm-transfer context. Official documentation · Oct 15, 2026Source | Supported5.6 / 5.6 pts Warm transfer provides prior conversation context and an operator summary. Official documentation · Oct 15, 2026Source |
Depth checkFallback when call setup or agent failsConfigure fallback handling when the voice agent or its telephony connection cannot serve a call.Ask for a demonstrationDemonstrate the configured fallback for an unavailable agent or destination. A scenario to run with the supplier; not a completed product test. | Not verified0–6.4 / 6.4 pts This specific workflow has not been established by the reviewed evidence. Not verified · Oct 15, 2026Source | Supported6.4 / 6.4 pts Configured fallback transcribers can take over after provider failure. Official documentation · Oct 15, 2026Source |
| Live actions and handoff 20% base weight | ||
| Core capabilityLive business actionsCall a tool, webhook or API during a conversation. | Supported4 / 4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported4 / 4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
| Core capabilityHuman or specialist handoffTransfer a conversation to a human or another configured specialist. | Supported4 / 4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported4 / 4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
Depth checkStructured action argumentsDefine tool parameters or structured fields so a business action receives inspectable values.Ask for a demonstrationCall a booking or CRM tool and inspect the arguments sent for the requested action. A scenario to run with the supplier; not a completed product test. | Supported5.6 / 5.6 pts Custom tools define typed parameters and authentication headers separately. Official documentation · Oct 15, 2026Source | Supported5.6 / 5.6 pts Function tools define structured parameters for external actions. Official documentation · Oct 15, 2026Source |
Depth checkContext-preserving handoffPass conversation context or a summary to the next agent or human during a handoff.Ask for a demonstrationTransfer a call after collecting information and show what the receiving person or agent receives. A scenario to run with the supplier; not a completed product test. | Supported6.4 / 6.4 pts Transfer tools support human warm-transfer context. Official documentation · Oct 15, 2026Source | Supported6.4 / 6.4 pts Warm transfer provides prior conversation context and an operator summary. Official documentation · Oct 15, 2026Source |
| Testing and call operations 16% base weight | ||
| Core capabilityPre-launch agent testingTest agent conversations before sending production traffic. | Supported3.2 / 3.2 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported3.2 / 3.2 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
| Core capabilityCall logs and monitoringInspect call records, transcripts or operational analytics. | Supported3.2 / 3.2 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported3.2 / 3.2 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
Depth checkRepeatable scenario testingRun saved or generated test scenarios with outcomes or evaluation results.Ask for a demonstrationRun the same successful and failing scenarios after a prompt change and inspect the results. A scenario to run with the supplier; not a completed product test. | Supported4.8 / 4.8 pts Simulation cases are rerunnable and graded against success criteria. Official documentation · Oct 15, 2026Source | Supported4.8 / 4.8 pts Simulation suites rerun scenarios with explicit pass/fail results. Official documentation · Oct 15, 2026Source |
Depth checkVersioned agent changesInspect prior agent configurations and restore or select a previous version.Ask for a demonstrationChange an agent instruction, then show how to return production to its earlier version. A scenario to run with the supplier; not a completed product test. | Supported4.8 / 4.8 pts Published versions and environment tags select the production configuration. Official documentation · Oct 15, 2026Source | Supported4.8 / 4.8 pts Assistants retain published versions and restoration controls. Official documentation · Oct 15, 2026Source |
| APIs and business connections 12% base weight | ||
| Core capabilityDeveloper APIs or webhooksManage agents or exchange conversation data using programmable interfaces. | Supported2.4 / 2.4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported2.4 / 2.4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
| Core capabilityBusiness or telephony connectorsUse supplied CRM, calendar, contact-center or telephony integrations. | Supported2.4 / 2.4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported2.4 / 2.4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
Depth checkAuthenticated business-tool accessConfigure authentication or protected credentials for calling an external business tool.Ask for a demonstrationShow a business tool connection with its credentials separated from the spoken conversation. A scenario to run with the supplier; not a completed product test. | Supported3.2 / 3.2 pts Custom tools define typed parameters and authentication headers separately. Official documentation · Oct 15, 2026Source | Not verified0–3.2 / 3.2 pts This specific workflow has not been established by the reviewed evidence. Not verified · Oct 15, 2026Source |
Depth checkStructured post-call event exportSend or retrieve post-call structured results and call identifiers through an API or webhook.Ask for a demonstrationFinish a test call and inspect its structured results in an external system. A scenario to run with the supplier; not a completed product test. | Supported4 / 4 pts Structured extraction results are accessible through call_analyzed events or Get Call. Official documentation · Oct 15, 2026Source | Not verified0–4 / 4 pts This specific workflow has not been established by the reviewed evidence. Not verified · Oct 15, 2026Source |
| Configurable conversational AI 19.5% base weight | ||
| Core capabilityBusiness knowledge groundingProvide business documents, website information or a knowledge source for answers. | Supported2.4 / 2.4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported2.4 / 2.4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
| Core capabilityConfigurable conversational behaviorConfigure agent instructions, dialogue paths or model behavior. | Supported2.4 / 2.4 pts US numbers, SIP/web voice, tools, tests and knowledge. Official documentation · Oct 15, 2026Source | Supported2.4 / 2.4 pts Phone/web agents, tools, Squads, tests and business integrations. Official documentation · Oct 15, 2026Source |
Depth checkManage and refresh grounded knowledgeUpdate or replace business knowledge used by the conversational agent and inspect its configured source.Ask for a demonstrationChange a policy in a knowledge source and demonstrate how the agent’s source is refreshed. A scenario to run with the supplier; not a completed product test. | Supported3.2 / 3.2 pts Knowledge sources and indexing can be managed per agent. Official documentation · Oct 15, 2026Source | Not verified0–3.2 / 3.2 pts This specific workflow has not been established by the reviewed evidence. Not verified · Oct 15, 2026Source |
Depth checkExplicit action or escalation boundariesConfigure a rule that restricts the agent’s permitted action or escalates an out-of-scope request.Ask for a demonstrationAsk for a restricted action and show the configured refusal or human escalation. A scenario to run with the supplier; not a completed product test. | Supported4 / 4 pts Guardrails configure prohibited-content detection and replacement behavior. Official documentation · Oct 15, 2026Source | Not verified0–4 / 4 pts This specific workflow has not been established by the reviewed evidence. Not verified · Oct 15, 2026Source |
Depth checkConfigure backup speech-synthesis providersDemonstrate "Configure backup speech-synthesis providers" with test data. Show the result, an exception case, and the required plan.Ask for a demonstrationDemonstrate "Configure backup speech-synthesis providers" with test data. Show the result, an exception case, and the required plan. A scenario to run with the supplier; not a completed product test. | Supported2.5 / 2.5 pts Retell documents fallback to another TTS provider after provider failure. Product changelog documents feature; confirm current compatible voice models and local contract. Official documentation · Oct 21, 2026Source | Supported2.5 / 2.5 pts An ordered backup-voice list can switch providers after a qualifying voice error. Not every outage/error is recoverable; provider, language and voice compatibility must be checked. Official documentation · Oct 21, 2026Source |
Depth checkConfigure backup speech-recognition providersDemonstrate "Configure backup speech-recognition providers" with test data. Show the result, an exception case, and the required plan.Ask for a demonstrationDemonstrate "Configure backup speech-recognition providers" with test data. Show the result, an exception case, and the required plan. A scenario to run with the supplier; not a completed product test. | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source | Supported2.5 / 2.5 pts Manual ordered transcription fallbacks and optional automatic fallback are configurable. Fallback may route audio to another provider; supported languages and retention terms vary by provider. Official documentation · Oct 21, 2026Source |
Depth checkSet custom pronunciation for names and termsSet a custom pronunciation for a sample name. Compare two supported voice models and show any model or language limitations.Ask for a demonstrationSet a custom pronunciation for a sample name. Compare two supported voice models and show any model or language limitations. A scenario to run with the supplier; not a completed product test. | Limited1.3 / 2.5 pts Custom pronunciation accepts word, phonetic alphabet and pronunciation values. Pronunciation support is voice/model-dependent; availability must be demonstrated for selected language/model. Official documentation · Oct 21, 2026Source | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source |
| Operational detail 12.5% base weight | ||
Depth checkInspect latency by voice-pipeline componentDemonstrate "Inspect latency by voice-pipeline component" with test data. Show the result, an exception case, and the required plan.Ask for a demonstrationDemonstrate "Inspect latency by voice-pipeline component" with test data. Show the result, an exception case, and the required plan. A scenario to run with the supplier; not a completed product test. | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source |
Depth checkConfigure reminders after caller silenceDemonstrate "Configure reminders after caller silence" with test data. Show the result, an exception case, and the required plan.Ask for a demonstrationDemonstrate "Configure reminders after caller silence" with test data. Show the result, an exception case, and the required plan. A scenario to run with the supplier; not a completed product test. | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source |
Depth checkChoose a separate action when voicemail answersDemonstrate "Choose a separate action when voicemail answers" with test data. Show the result, an exception case, and the required plan.Ask for a demonstrationDemonstrate "Choose a separate action when voicemail answers" with test data. Show the result, an exception case, and the required plan. A scenario to run with the supplier; not a completed product test. | Supported2.5 / 2.5 pts Voicemail handling can hang up, leave a recorded message or generate a personalized message. Product changelog; detection is not guaranteed and local outbound-calling permissions remain separate. Official documentation · Oct 21, 2026Source | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source |
Depth checkRedact sensitive fields from call transcriptsDemonstrate "Redact sensitive fields from call transcripts" with test data. Show the result, an exception case, and the required plan.Ask for a demonstrationDemonstrate "Redact sensitive fields from call transcripts" with test data. Show the result, an exception case, and the required plan. A scenario to run with the supplier; not a completed product test. | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source |
Depth checkVerify cryptographic post-call webhook signaturesDemonstrate "Verify cryptographic post-call webhook signatures" with test data. Show the result, an exception case, and the required plan.Ask for a demonstrationDemonstrate "Verify cryptographic post-call webhook signatures" with test data. Show the result, an exception case, and the required plan. A scenario to run with the supplier; not a completed product test. | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source | Not verified0–2.5 / 2.5 pts This specific check has not been verified. Missing evidence does not mean the capability is absent. Ask for a demonstration in the proposed plan. Not verified · Oct 21, 2026Source |
| AI usage and limits | Configurable real-time speech agents use prompts or conversation flows, knowledge retrieval and tools to complete tasks or transfer to humans.
| Assistants combine speech recognition, language models and generated voice; tools and Squads support actions and context-preserving handoffs.
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| Additional costs to ask about |
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| Integration shortlist |
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| Research date | Oct 15, 2026 Full source record → | Oct 15, 2026 Full source record → |