OpenAI
The AI company behind ChatGPT and the GPT models. Founded in 2015 and based in San Francisco.
What it tells you about a developer
Building on OpenAI’s API means the developer has integrated a language model into software: handling prompts, costs, errors, and unpredictable output. Those skills transfer directly to Anthropic and Google models, because the APIs are similar by design.
OpenAI trains the GPT family of language models and sells access to them two ways: ChatGPT for people, and a paid API for developers building products. When a resume says a developer built on OpenAI, it means their software sends requests to OpenAI’s models and works with the answers. Anthropic and Google are the closest peers.