Rainbow Indent Guide

Multi-level rainbow indent guides for Eclipse. Deeply nested code becomes readable at a glance: every indentation level gets its own colour, and the braces of a block are repainted to match their guide, so the vertical line and the braces read as one shape.

What it does

• Rainbow guides — seven configurable colours, one per nesting level, cycled beyond the seventh.
• Matching braces — the { and } take the colour of the guide they belong to.
• Rainbow parentheses — round brackets are coloured by nesting depth, with their own palette, so foo(bar(baz(x))) reads at a glance.
• Active block — the guide holding the caret keeps its level colour and lights up. Hover a guide to light it up, click to pin it there.
• Unbroken lines — blank lines and comments no longer interrupt the guides, and each guide is stroked in one piece, so thin or barely opaque lines stay clean instead of breaking up into dots.
• Mixed indentation warning — optionally, a guide that doesn't line up with its braces is greyed out, then blinks as it takes its colour back once you fix it.
• Sharp on HiDPI — guide positions are computed at sub-pixel precision, so lines don't drift right on deep levels under DPI scaling.

Getting started

Java, XML, properties, JSP, HTML, CSS, JS, PHP and C/C++ are enabled out of the box — nothing to configure on first launch. Everything is adjustable under Window > Preferences > General > Editors > Text Editors > Indent Guide, with the colours on the Style subpage. Changes apply immediately, without reopening editors.

Guides follow the file's content type, so a file needs to be opened with the editor registered for it. If a file shows no guides, check Right-click > Open With.

Compatibility

Tested on Eclipse 2020-03, 2024-09 and 2026-06, and it works with Show only selected element and Clone Editor. Java 8 is the minimum, deliberately: many people are stuck on older installs they can't upgrade, and drawing indent guides needs nothing from a newer language level.

Before you install

Already running another Indent Guide plug-in? Uninstall it first. This fork declares a conflict with jp.sourceforge.pdt_tools.indentGuide and Certiv Analytics' net.certiv.tools.indentguide, so p2 will refuse the install rather than leave you with duplicate preference pages and two painters drawing over each other.

A fork of the abandoned Indent Guide plug-in, rebuilt for current Eclipse releases and released under EPL 1.0.
Source, issues and full history: github.com/SimonePlatania/RainbowIndentGuide