Most running shoe uppers are cut, sewn, and glued together from several pieces of fabric — a process that hasn’t changed much in decades. LightSpray™ throws that out entirely. Developed by On, it’s a manufacturing process that sprays an entire shoe upper as one seamless piece, using a robotic arm rather than a sewing machine.
An Unlikely Starting Point
The idea behind LightSpray™ reportedly came from an unexpected place — a member of On’s innovation team was inspired by a video of a hot glue gun creating spider-web patterns. That concept eventually became a fully automated production process built at On Labs in Zurich, turning raw material into a finished upper in around three minutes.
How the Process Actually Works
A traditional upper goes through several separate stages: yarn production, weaving or knitting the fabric, coloring, cutting the pieces to shape, then stitching and gluing them together. Each step adds time, waste, and energy use.
LightSpray™ replaces most of that with one continuous step. A robotic arm precisely sprays roughly 1.5km of filament directly onto the shoe, fusing it into a single, seamless upper with no laces and no separate pieces to join. The result is a shoe upper that’s lighter than a conventionally constructed one, largely because there’s simply less material and fewer components involved.
Why It’s Not Just a Manufacturing Trick
The environmental angle is a genuine part of the story here, not just marketing language. An independent life-cycle assessment found the process cuts carbon emissions by around 75% compared to On’s other racing shoe uppers, largely by removing water-heavy textile production and excess material waste from the process entirely.
What It’s Actually Used For
LightSpray™ first appeared in the Cloudboom Strike LS, a dedicated racing shoe built for competition rather than everyday training. Since then, the technology has expanded into training-focused models too — including the Cloudmonster range, where a LightSpray version pairs that seamless, ultra-light upper with the brand’s maximum-cushioning platform for higher-mileage training rather than race day alone.
What It Feels Like to Wear
Because the upper is sprayed as one continuous piece rather than assembled from parts, it tends to sit closer to the foot, often described as a “second-skin” feel. On’s own guidance notes that a LightSpray™ upper is designed to gradually mould to the shape of your foot over repeated wear, without stretching out or losing the secure lockdown a performance shoe needs. It’s built for road use specifically — On doesn’t recommend it for trail or technical terrain, where a more rugged upper construction holds up better.
Caring for a LightSpray™ Upper
Because the upper is a single fused piece rather than stitched fabric, it needs slightly different care than a traditional shoe. On specifically advises against machine washing, since it can affect the integrity of the sprayed filament over time. For everyday maintenance, simply brushing off dry dirt once it’s settled is enough to keep the upper looking and performing as intended.
Frequently Asked Questions
What is LightSpray™?
LightSpray™ is On’s automated manufacturing process that sprays a shoe’s entire upper as one seamless piece using a robotic arm, replacing traditional cutting, sewing, and gluing.
Is LightSpray™ a type of cushioning?
No. It’s an upper construction technology, separate from CloudTec®, which is On’s cushioning system. LightSpray™ affects the fit and weight of the shoe, not the sole.
Which shoes use LightSpray™?
It debuted in the Cloudboom Strike LS racing shoe and has since expanded to training-focused models, including a LightSpray version of the Cloudmonster.
Can LightSpray™ shoes be used off-road or on trails?
On doesn’t recommend it for trail or technical terrain. The technology is built specifically for road use.
Explore the Range
Curious to see LightSpray™ in a training shoe? Browse our Cloudmonster collection, or explore the full range below.
