Deepgram vs Vapi: pricing, features and which to choose

Deepgram is a San Francisco speech AI company founded in 2015 by Scott Stephenson and Noah Shutty, two physicists who had worked on dark matter detection, and it went through Y Combinator. It builds its own speech models instead of reselling others. In January 2026 it raised a $130 million Series C led by AVP at a $1.3 billion valuation, taking total funding past $215 million, and Stephenson told TechCrunch the company was cash-flow positive the year before. Investors include In-Q-Tel, Madrona, Tiger, Twilio and SAP. Deepgram says more than 1,300 organisations use its models, among them the meeting notetaker Granola, the voice agent platform Vapi and Twilio. Alongside the round it bought OfOne, a Y Combinator startup that builds drive-through ordering agents for quick-service restaurants.

Deepgram offers four API families. Speech-to-text covers pre-recorded files over REST and live audio over WebSockets, with speaker diarization, smart formatting, keyterm prompting for jargon and automatic language detection across 45-plus languages. Text-to-speech, sold under the Aura name, streams spoken replies for agents. The Voice Agent API bundles transcription, a language model and speech into one WebSocket so developers do not have to orchestrate three vendors. Audio Intelligence adds summaries, topic detection, sentiment and intent on top of transcripts. A typical build sends a phone or meeting audio stream to the API and receives word-level timestamps within a few hundred milliseconds. Developers get SDKs for Python, JavaScript, Go and .NET, plus a playground in the console for comparing models on their own audio.

Deepgram is an API for developers, so anyone who wants a finished meeting notetaker or dictation app should look at Otter.ai or similar products built on top of it. Self-serve support is limited to the community and Discord until you sign an enterprise contract. AssemblyAI is the closest rival, with comparable accuracy, strong audio intelligence features and similar per-hour pricing. Speechmatics is stronger on broad language coverage and on-premises deals in Europe, and OpenAI's speech models are convenient for teams already on the OpenAI API. ElevenLabs leads on expressive text-to-speech, where Deepgram's Aura voices are tuned for speed over range. Pick Deepgram when you need low-latency streaming transcription for agents or call analytics at high volume, especially if self-hosting is a requirement.

Vapi is a San Francisco company that sells the plumbing behind AI phone agents. Jordan Dearsley and Nikhil Gupta, classmates from the University of Waterloo, went through Y Combinator with a productivity app called Superpowered. In 2023 Dearsley built an AI therapist to talk to on walks, found that startups wanted the low-latency voice layer underneath it, and the pair relaunched as Vapi in 2024. In May 2026 it raised a $50 million Series B led by Peak XV at about a $500 million valuation, bringing total funding to $72 million, according to TechCrunch. The company says it has handled more than 1 billion calls and has over 1 million developers on its self-serve platform. Enterprise customers include Amazon Ring, which routes all of its inbound support calls through Vapi, plus Intuit, New York Life and Kavak.

A Vapi agent is a configuration that wires together three parts: a transcriber that turns caller speech into text, a language model that decides what to say, and a voice that speaks the reply. You set these up in the dashboard or through the API, write a system prompt, and attach tools so the agent can book appointments, look up orders or transfer to a human. Vapi supplies phone numbers, or you bring your own through Twilio, Vonage or SIP. Squads let several specialised agents hand a call to each other. Testing and simulation features run scripted calls against an agent before it reaches customers, and observability dashboards flag failed calls. Web and mobile SDKs cover in-app voice. Common uses are customer support lines, lead qualification, appointment scheduling and outbound sales calls.

Vapi expects you to write prompts, configure tools and read logs, so non-technical teams usually need a developer or an agency to get an agent into production. Total cost is harder to predict than a flat per-minute rate because it depends on which models you pick. Retell AI offers a similar developer platform with simpler bundled pricing and strong turn-taking, and Bland AI targets enterprises that want a more managed service with its own hosted models. ElevenLabs Agents is the easier choice if you already use ElevenLabs voices and want one vendor. Pick Vapi if you have engineers, expect high call volumes and want freedom to change speech, language and voice providers as models improve. Choose Retell or a no-code tool if your team wants a working receptionist this week without touching an API.