Light Level 2025

Pressing F9 toggles the display of block-light levels on top of solid blocks, and pressing F3 shows both block-light and sky-light values together. The overlay is rendered only for the player, and a block that sits above the target does not hide the text. Rendering is skipped for the block the player is looking at, so the number stays readable.

To reduce work each frame, the mod stores the positions of blocks and the text drawn for them in a cache. The cache update frequency adjusts automatically to the frame rate, refreshing more often in high-FPS environments and less often in low-FPS ones. The interval can also be set by hand through cache.update in the config file. A config field also controls the general behavior. The mod is open source under the MIT License and is a rewrite inspired by LightLevel from parzivail, with some improvements. Its author notes that large language models were used for code proofreading and changes.

Fabric Loader and Fabric API are required. The mod is a client mod: only the client needs it, and servers run without it. Files are published for Fabric across four game versions, 1.21.5 – 1.21.8, with 1.21.8-final as the latest release from 2025-07-22. Snapshot builds are also published.