A moodboard communicates "this kind of feeling" through images instead of words. Reference photos, color swatches, textures, and type samples are arranged freely as a collage — not on a grid — to build a shared sense of an as-yet-undefined mood: cold or warm, luxurious or playful, between a team and a client.
It's often confused with a style tile, but the two belong to different stages. A moodboard belongs early, while still exploring direction — it doesn't need to answer "so what's the actual hex code?" yet. Once a moodboard narrows the direction down, the next step is a style tile that pins down the real hex codes and font names.
A moodboard itself isn't a deliverable — it's a conversation tool. Its job is to let a client point at a photo and say "that one, more like that."
When to use
Use it early, when a brand's tone or visual direction is hard to agree on in words alone. Once you need actual color and font decisions, move on to a style tile.