How On’s LightSpray Robot Is Redefining Marathon Running

This robot is making On’s spray-on marathon sneaker, its fastest-ever distance shoe.

 

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Ahead of the London Marathon on Sunday, 26 April 2026, Swiss sportswear brand On brought its pioneering LightSpray robot to the British capital for the first time. Held at a pop-up in Hanover Square from 24–26 April, the event allowed runners and enthusiasts to witness live shoe production, try on the latest models, and take part in movement sessions. It marked a significant moment for On’s innovative technology, which is reshaping the language of high-performance running footwear.

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LightSpray represents a radical departure from traditional shoe manufacturing. Most running shoes involve dozens, sometimes hundreds, of hands cutting, stitching, gluing, and assembling multiple components over hours. LightSpray condenses this into a single automated step: a robotic arm sprays a continuous 1.5-kilometer filament of polymer directly onto a shoe last, forming an ultralight, seamless, one-piece upper in just three minutes.

The result is a sock-like, laceless upper, often nicknamed the “Spiderman” shoe for its web-like, stretchy mesh appearance. It delivers a second-skin fit with no seams or pressure points that could cause blisters, alongside exceptional breathability and minimal weight, with some uppers weighing as little as 30 grams. The technology also minimizes waste by using precisely the amount of material needed and reduces CO₂ emissions from upper production by about 75% compared to On’s other racing shoes.

On Cloudboom Strike LS Initial Thoughts – The Running Channel

Scott Maguire, On’s president and COO, and a former Dyson alum, explained the innovation’s significance: “It’s pioneering because it completely reinvents how a shoe upper is made. It moves it from a complex, multi-step assembly process to a revolutionary single-step—the ultralight uppers are literally sprayed, not built.” Beyond efficiency, it enables precise engineering tailored to performance needs.

On developed the entire system in-house, including the robots, spray paths, and software. Initial production took place in Zurich labs, but scaling accelerated with a new “robot farm” in Busan, South Korea, housing 32 robots and boosting LightSpray output by 30-fold. This shift moved the technology from limited elite prototypes toward broader consumer access.

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The technology’s real-world proof comes through elite athletes. Kenyan runner Hellen Obiri first wore a LightSpray prototype Cloudboom Strike in 2024, securing victories in major marathons including Boston twice, New York with a course record of 2:19:51 in 2025, and a strong second-place finish, with a PB of 2:15:53, at the 2026 London Marathon behind Tigst Assefa.

Other successes include Yeman Crippa’s Paris Marathon win and Ironman triumphs by triathletes such as Kristian Blummenfelt and Solveig Løvseth. These wins highlight how the lightweight, responsive design translates into real speed and comfort over long distances.

On’s new LightSpray CloudMonster 3 Hyper running shoe is built by robots in 3 minutes flat | Popular Science

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The Cloudboom Strike LS serves as On’s premier racing flat. It pairs the sprayed upper with a carbon-plated Helion HF superfoam midsole for maximum energy return and propulsion. Priced around $330, it is a laceless super shoe optimized for race day, offering a direct, responsive ride with minimal material between foot and foam.

The Cloudmonster 3 Hyper, launched more recently, brings LightSpray into training and longer efforts. It features a max-stack build of around 49mm at the heel and 43mm at the forefoot, with a 6mm drop, using plush Helion HF foam—77% more than the original Cloudmonster—for high-mileage cushioning without a plate. Reviewers praise its versatility: forgiving at easy paces yet responsive and rockered enough for faster efforts or marathon racing. After more than 50 miles of testing, it maintained comfort, stability, and durability even on varied terrain.

Both models fit true to size with a snug, performance-oriented feel. The upper adapts subtly over time to the foot’s shape for a custom lockdown. They excel on roads but are not suited for trails, while care involves hand-washing or brushing rather than machine cycles.

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At Hanover Square, visitors watched the robot in action as it produced Cloudmonster 3 Hyper and Cloudboom Strike models. The immersive space, created with PlayLabs, included audio from Obiri sharing her experience, alongside workshops and “Dream Run” test opportunities. Shoes were available nearby at On’s Regent Street store.

This activation aligned with marathon weekend energy and On’s global LightSpray Tour, with future stops in Paris, Sydney, and Berlin. It helped democratize access to cutting-edge running technology, allowing everyday runners to experience what had once been limited to elites.

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LightSpray is not only about lighter shoes. It signals a future of localized, on-demand production. Robots enable rapid iteration, with new sizes or designs created in minutes rather than weeks. Reduced components and waste point toward greater sustainability and circularity. On plans more robot farms globally, expanding the technology across product lines.

For runners, the benefits include superior fit, lower weight, fewer distractions from gear, and potentially faster times through improved energy transfer and comfort. While premium-priced and initially limited, wider availability makes championship-level innovation more accessible.

Critics might note that the snug fit may suit narrower feet best, or question the long-term durability of the filament upper, although On claims parity with standard shoes. Early testers report no major issues after significant mileage.

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As marathon fields grow more competitive and technology pushes toward ever-narrower margins, On’s LightSpray positions the brand as a leader, blending Swiss engineering precision with bold futurism. The robot in London was not just demonstrating a shoe. It embodied a new chapter where manufacturing speed, performance, and sustainability converge.

For runners in New York City or elsewhere, the technology promises more efficient, enjoyable miles. Whether chasing personal records or simply moving better, the sprayed-on future feels closer than ever. On’s message resonates clearly: dreams are made real in LightSpray. Watch for expanded drops and future tour stops—the next chapter of running is quite literally being sprayed into existence.