Data Cascade

In Eleventy, data is merged from multiple different sources before the template is rendered. The data is merged in what Eleventy calls the Data Cascade.

Sources of Data

When the data is merged in the Eleventy Data Cascade, the order of priority for sources of data is (from highest priority to lowest):

1. Computed Data
2. Front Matter Data in a Template
3. Template Data Files
4. Directory Data Files (and ascending Parent Directories)
5. Front Matter Data in Layouts (this moved in 1.0)
6. Configuration API Global Data
7. Global Data Files

Example

---
title: This is a Good Blog Post
tags:
  - CSS
  - HTML
layout: my-layout.njk
---

---
title: This is a Very Good Blog Post
author: Zach
tags:
  - JavaScript
---

Note that when my-template.md and my-layout.njk share data with the same object key (title and tags), the “leaf template” my-template.md takes precedence.

The data cascade results in the following data when my-template.md is rendered:

{
	"title": "This is a Good Blog Post",
	"author": "Zach",
	"tags": ["CSS", "HTML", "JavaScript"],
	"layout": "my-layout.njk"
}

By default in v1.0, Eleventy does a deep data merge to combine Object literals and Arrays. If you want to opt-out of this behavior and revert to a simple top level merge (Object.assign) from the different data sources, you can turn off Data Deep Merge. You can override this on a per-property basis too—read more at the Data Deep Merge documentation.

From the Community

I Finally Understand Eleventy’s Data Cascade

+ Add yours!

×49 resources via 11tybundle.dev curated by Bob Monsour.

• exhibitionism — tlohde (2025)
• Last modified date of Eleventy posts — Josh Sherman (2025)
• Data vs. Collections in Eleventy — Mark Dyck (2025)
• Rendering FreeMarker and Python page templates with 11ty — Tobias Fedder (2025)
• Generating content driven CSS with Eleventy — Sami (2025)

Other pages in Using Data

• Eleventy Supplied Data
• Data Cascade
  • Front Matter Data
    • Custom Front Matter
  • Template & Directory Data Files
  • Global Data Files
  • Config Global Data
  • Computed Data
• JavaScript Data Files
• Custom Data File Formats
• Validate Data