OpenAI is reportedly testing a new feature or product codenamed "Sonata," and it could be related to music or audio-related experiences on ChatGPT.

As spotted by Tibor on X, there are fresh OpenAI-related hostnames spotted recently.

The first is sonata.openai.com (dated 2026-01-16) and sonata.api.openai.com (dated 2026-01-15).

This means OpenAI (or its infrastructure) has started using a new subdomain, “sonata,” on both its main domain and its API domain.

A new hostname means OpenAI is testing a new service. OpenAI hostnames often point to a web-facing product page, internal tool, or a web app.

The codename is "sonata," which refers to a multi-movement instrumental music composition. However,  it can refer to other things too (like a car model, a company name, or a drug brand).

This is a good reminder that a codename doesn’t tell you what the feature is.

Recently, ChatGPT gained a new feature that makes it possible to reliably find specific chat details.

"When reference chat history is enabled, ChatGPT can now more reliably find specific details from your past chats when you ask," OpenAI confirmed in updated release notes.

Any past chat used to answer your question now appears as a source, so you can open and review the original context.

OpenAI is also improving dictation capabilities in ChatGPT for all logged-in users.