Side-by-side comparison of AI visibility scores, market position, and capabilities
Developer-first voice AI infrastructure API for building phone agents; low-latency streaming pipeline with multi-LLM and telephony support competing with Vapi for production voice applications.
Retell AI is a voice AI infrastructure platform providing APIs and tools for building conversational AI phone agents with low latency, natural turn-taking, and integration with major telephony providers and LLM providers. Founded in 2023 and headquartered in San Francisco, Retell AI has rapidly gained developer traction for its straightforward API, extensive documentation, and emphasis on production-grade reliability for AI voice applications in customer service, sales, and healthcare use cases.
SF YC W24 AI meeting notes at $16.8M revenue 2024 with only 4 employees and cash flow positive; $3M seed from ex-Stripe/Tableau founders competing with Otter.
Circleback is a San Francisco-based AI-powered meeting notes and action tracking platform — backed by Y Combinator (W24) with $3 million in total funding including a $2.5 million seed in November 2024 from YC, Rebel Fund, Pioneer Fund, Transpose Platform, and angels including Kulveer Taggar, Oliver Jung, JJ Fliegelman, Rich Aberman, and Jason Freedman — generating $16.8 million in annual revenue in 2024 with only 4 employees, achieving cash flow positive status through primarily organic growth, and serving thousands of paying customers. Founded by Ali Haghani (ex-Stripe) and Kevin Jacyna (ex-Tableau), Circleback automatically joins meetings (Zoom, Google Meet, Microsoft Teams), transcribes conversations with AI, generates structured meeting notes with action items, and distributes summaries to participants and connected tools (Slack, Notion, HubSpot, Salesforce).
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