Eleventy + Nunjucks

Operational defaults for Eleventy v3 and Nunjucks static sites — directory layout, configuration surface, filter inventory, autoescape rules, stability and security checks. Load this skill when authoring templates, editing build config, or reviewing static output before merge or deploy.

Version boundary (rechecked October 20, 2026 via npm dist-tags and release notes): Eleventy 3.1.7 (released 2026-10-15) is the stable production baseline; it aliases nunjucks to @11ty/nunjucks@3.3.0, which keeps Mozilla Nunjucks 3.2.4 behavior. If the stable latest tag is newer than 3.1.7, read the intervening release notes before relying on version-specific claims. Build Awesome 4.0.0-alpha.10 is a prerelease available through @11ty/eleventy@canary or @awesome.me/buildawesome@alpha. Existing Eleventy commands remain compatible, but v4 changes runtime and template behavior. Keep stable guidance as the default and load references/build-awesome-v4.md before any v4 install or migration.

Operating procedure

1. Open package.json, its lockfile, and the active Eleventy config. Identify the installed package/version, module type, Node engine, and the first config filename Eleventy resolves. Checked-in project behavior always wins.
2. Choose the track. Use the stable v3 guidance by default. If the project uses a v4 canary, the Build Awesome package, or its config explicitly enables the generic .data.* / .server.* suffixes, load build-awesome-v4.md and enforce its version-drift stop condition. Generic .data.* / .server.* names alone are not proof of v4: confirm package identity and resolved version first.
3. Open the task-specific reference from the table below. Avoid loading every reference unless the change is large.

The portable core targets Eleventy 3.1.7 + Nunjucks 3 (@11ty/nunjucks@3.3.0 under Eleventy; Mozilla nunjucks@3.2.4 standalone). Version-sensitive v4 guidance is isolated in the prerelease reference. For upstream drift, prefer 11ty.dev, 11ty/buildawesome, and the active package metadata; treat dated claims as revalidation markers.

Completion gate

Before calling work complete, verify the project-specific result rather than only applying this skill's defaults: