Redlining (or Redline) is marking up a UI design hand-offs by adding red lines indicating spacing and sizing of design elements. Redlining is done to communicate fine details of the design to development team or other team members who don’t have direct access to the source design files.
Redlining UX design deliverable comes in various forms. Redlines can be annotated static images (most commonly mocks or comps), or interactive documents.
Historically redlining was used in architectural drawings for editorial notes and revisions.
UX Redlining Tools
Practically any modern UX design app supports redlining through plugins.
Here are some popular UX redlining tools:
- Avocode (works with Sketch, Adobe XD, Figma, Photoshop and Illustrator)
- Sketch Measure (Sketch plugin)
- Figma Redlines Plugin
- Figma Redlines Component
- SpecKing (Photoshop plugin)
It is worth mentioning that many modern design tools have other hand-off features that are similar to redlining or completely replace the need to redline the documents. You can find a comprehensive list of design tools and see which ones have redlining and other hand-off features at UX tools website:
Remember that redlining is just one aspect of a successful hand off. I highly recommend taking a look at A Guide to Successful Design Handoffs by Mohammed Bilal for a comprehensive overview.