Chroma’s persistence pitfall: ephemeral Client() vs PersistentClient

A DEV Community post published on October 3, 2026 walks through getting started with Chroma and flags a persistence pitfall that users of its embedded mode can hit. Chroma is described as an open-source embedding database under the Apache 2.0 license, built Python-first, with its core rewritten in Rust starting with v0.4.

Setup is deliberately minimal. Running pip install chromadb is enough to begin using it: no server, no ports, and no API keys are needed, because embedded mode is the default way to run Chroma.

The catch is where the data ends up. According to the post, the client you pick determines whether anything survives a restart. PersistentClient writes data to local disk in the form of SQLite plus Parquet, so it stays put. The basic Client() is ephemeral and loses data when the process restarts — the pitfall the post sets out to warn readers about. For anyone treating Chroma as a local embedding store rather than a hosted service, that difference is the detail worth checking before writing to it.

The post does not include any response from Chroma or its maintainers about the two client behaviors, and it mentions no release notes, patches, or other follow-up. As of this reporting, the account stands as a single how-to write-up covering the v0.4-era Rust core and the gap between PersistentClient and Client() in embedded mode, with no further developments or official statement available.