---
title: "A Layer as constructor"
description: "Sam Goodwin compares an Effect Layer that builds a service to a constructor."
group: concept
terms:
  - "Layer constructor"
  - "layer as constructor"
sources:
  - https://youtu.be/MtKHzAH6uXM?t=1125
---

# A Layer as constructor

Sam compares the constructor pattern to a Layer and uses a React component as an analogy. In the same discussion, he connects the pattern to infrastructure policies. [Watch from 18:45](https://youtu.be/MtKHzAH6uXM?t=1125).

See [Sam Goodwin on Alchemy](/lore/devtools-fm-sam-goodwin-alchemy) and [cartridges](/lore/cartridges).