Retell AI API
Retell AI grades A+: self-serve signup with no credit card, $10 in free credits, 20 free concurrent calls, published modular per-minute pricing, public docs, official Node.js and Python SDKs, and webhooks. Enterprise adds scale and compliance rather than gating access.
Frequently asked questions
Retell AI scores A+ on the API Report Card. Retell AI grades A+: self-serve signup with no credit card, $10 in free credits, 20 free concurrent calls, published modular per-minute pricing, public docs, official Node.js and Python SDKs, and webhooks. Enterprise adds scale and compliance rather than gating access.
Retell AI has a workable official integration path. Most engineering teams can build against it directly. Open API: self-serve, documented, with SDKs
Retell AI is a voice AI agent platform for building, testing, deploying, and monitoring phone and chat agents.
Software and data tools. Developers create agents through the dashboard or API, buy a managed number or connect SIP trunking, attach knowledge bases and CRM tools, subscribe to webhooks for real-time call events, and run simulation tests before deploying.
Retell AI is one of the most cited voice agent platforms alongside Vapi and Bland AI. It is a Y Combinator company with broad adoption among AI-native startups building phone automation; public customer counts are not disclosed.
Retell holds agent configurations, call recordings, transcripts, and analysis for its customers' voice agents. It is developer infrastructure rather than a vertical system of record; the business data agents act on lives in the systems the agents call into.
A product of the 2023 to 2024 voice AI wave, built API-first: webhook-driven call events with no polling, node-based flow builder alongside prompt-based agents, simulation and A/B testing, an MCP server for tools like Cursor and Claude Desktop, and modular pay-as-you-go metering.
Third-party cost analyses note real per-minute cost combines four components (voice infrastructure, TTS, LLM, telephony) and lands near $0.13 to $0.31 per minute in production, above the $0.055 base rate. Full sourced list under Sources below.
Common alternatives include Vapi, Bland AI, ElevenLabs, LiveKit, Synthflow. Graded alternatives appear under "More from the report card" below.
Grades measure one thing: can a customer's engineering team get their own data out programmatically? We check six things (whether a real API exists, how access is gated, data coverage, auth quality, docs and developer experience, and stability) and roll them into a letter grade. Grades get re-verified, and they only move on evidence.