Perplexity

From answer engine to developer platform

Perplexity launched its answer engine on December 7, 2022. Investor IVP led its $73.6 million Series B in January 2024. The first product expansion included mobile apps, image search and an interactive search companion.

The founding team

The four co-founders built a company around AI-assisted information access. An account from investor NEA describes the early team's short paid work trials and rapid product iterations. It identifies Srinivas and Yarats as the initial co-founders, followed by Ho and Konwinski.

The API changed in 2026

Support for Sonar Chat Completions ended on September 27, 2026. Synchronous and streaming requests continue through a gradual conversion to Agent API requests. The old asynchronous route is unsupported. The Agent API also serves other developers' models; hosting them does not make Perplexity their author.

Historical Sonar API services

Sonar Pro, Sonar Reasoning Pro and Sonar Deep Research were Sonar API offerings. Perplexity maps them to the Agent API effort settings fast, low and high, respectively. These settings control the service; they are not new names for the same model weights.

Practical guidance. The reviewed sources do not identify a separate trained model for each of these service names. They are included here as product history and are not counted as separate models.

Models covered here

Practical guidance. These articles cover Sonar, decision models, dense and late-interaction embeddings, privacy models and a reviewed local Computer checkpoint. Historical and sparsely documented repository variants remain under review.