Lucide vs Heroicons
Heroicons is the Tailwind set, with outline and solid sizes. Lucide stays on one 24px stroke grid.
- Heroicons fits Tailwind UI and has explicit 16, 20, and 24 sizes in the name.
- Lucide fits component libraries that expect a single outline style.
- Solid Heroicons are filled. Lucide icons are strokes. They should not share a button group.
Which one to open
Open Heroicons when the interface is already Tailwind and you want the outline or solid weight that Tailwind UI expects. Names carry the size, often 16, 20, or 24. Pick the size that matches the component. Open Lucide when a component library expects one outline style and a single 24px grid.
Heroicons is curated and smaller than Tabler. That is useful on a marketing page and a limit in dense admin chrome. The cards above open each collection.
Outline, solid, and the grid
Heroicons outline icons are strokes. Solid icons are filled. Lucide icons in this catalog are strokes on one grid. A solid Heroicon in a Lucide button group changes both the fill and the drawing. Scaling one Heroicon viewBox is a worse fix than choosing the size already in the name.
Neither set is a brand or flag library. Keep those in SVG Logos, Simple Icons, or a flag pack.
License
Lucide is ISC. Heroicons is MIT. Keep the notice for the set you ship. Neither license is CC BY, so a credit line on the page is not what these two ask for. Follow the upstream license. This site is not legal advice.