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LangChain Expression Language (LCEL)

LangChain Expression Language or LCEL is a declarative way to easily compose chains together. Any chain constructed this way will automatically have full sync, async, and streaming support.

If you're looking for a good place to get started, check out the Cookbook section - it shows off the various Expression Language pieces in order from simple to more complex.

Interface​

The base interface shared by all LCEL objects

Cookbook​

Examples of common LCEL usage patterns

Why use LCEL​

A deeper dive into the benefits of LCEL