Retell AI vs Vapi

Both tools offer partial white-label support and no-code agent builders. Retell AI edges ahead for agencies due to lower real production costs (0.085-0.415 vs 0.05-0.17 USD/min at worst case is actually Retell higher, but base per-min is $0.07 vs $0.05). However Retell AI has SOC 2 Type II (Vapi does not), no annual contract required (Vapi requires annual for best pricing), lower extra concurrency cost at $8/mo vs $10/mo, and 20 base concurrent calls vs 10. For agencies scaling multiple client deployments, the higher base concurrency, no annual lock-in, and SOC 2 certification provide meaningful advantages.

Both tools are API-first and support BYO-LLM and BYO-voice, but Vapi passes LLM and TTS costs through at cost while Retell bundles them into a fixed rate, giving engineering teams more granular cost control and flexibility. Vapi also has a lower real production cost ceiling at 0.05-0.17 USD/min versus Retell's 0.085-0.415 USD/min, meaning custom pipelines with variable model usage stay cheaper. The $50M Series B signals stronger infrastructure investment supporting custom engineering workflows.

For ecommerce support, cost efficiency and integrations matter most. Vapi's real production cost tops out at $0.17/min versus Retell AI's $0.415/min, a significant saving at volume. Vapi also integrates natively with Zapier, Google Calendar, Slack, GHL, and Make, giving broader ecommerce workflow connectivity. Both support warm transfer, knowledge base, and outbound campaigns. Retell AI holds SOC 2 Type II certification, but Vapi's lower cost ceiling and richer integration ecosystem edge it out for typical ecommerce order flow automation.

For HIPAA-bound healthcare workflows, two factors dominate: HIPAA BAA availability and security certifications. Retell AI holds SOC 2 Type II certification while Vapi does not. On HIPAA BAA, Retell AI restricts it to enterprise plans and Vapi offers it as a paid add-on, making Vapi slightly more accessible. However, Retell AI's SOC 2 Type II certification is a concrete, audited compliance credential that Vapi cannot match. For regulated healthcare use, that audited certification tips the decision toward Retell AI.

For high-volume outbound sales campaigns, cost and concurrency matter most. Retell AI has a base price of $0.07/min versus Vapi's $0.05/min, but Retell's real production cost tops out at $0.415/min versus Vapi's $0.17/min, making Retell potentially more expensive at scale. However, Retell includes 20 concurrent calls on the base plan versus Vapi's 10, and extra lines cost $8/mo versus $10/mo, giving Retell a clear capacity advantage. Retell also holds SOC2 Type II certification and requires no annual contract, while Vapi requires an annual commitment for best pricing. Both support native outbound campaigns and warm transfer. The higher base concurrency and lower expansion cost tip the decision toward Retell for call-center volume.

For an SMB receptionist use case, cost predictability and compliance matter. Retell AI has a lower base price ceiling with real production costs of 0.085-0.415 vs Vapi's 0.05-0.17, but Retell AI bundles LLM/TTS costs (no passthrough) giving more predictable invoicing for SMBs. Retell AI includes 20 concurrent calls vs Vapi's 10, which helps handle busy periods, and adds extra lines at $8/mo vs $10/mo. SOC 2 Type II certification on Retell AI adds trust for small business clients handling customer data. Both support no-code builder and warm transfer, but Retell's higher concurrency and compliance posture edge it ahead.