PaintNuts sets the industry standard for automotive touch-up paint, thanks to advanced technology that matches paint to vehicle registration. However, their powerful Colour Match Guarantee—a true market differentiator—was buried in website fine print, largely unknown to visitors.

Meanwhile, competitors highlighted similar guarantees upfront, putting PaintNuts at risk of being overlooked despite offering a superior product. This led to missed sales as customers looked elsewhere for reassurance that their purchase would be the perfect match.

The challenge for Door4 was clear: make the Colour Match Guarantee unmissable, give users more confidence, and recapture lost conversion opportunities.

Putting Trust Front and Centre with UX-Driven Guarantee Design

Door4 took a strategic, test-led approach to unlocking PaintNuts’ underutilised value proposition.
Recognising the emotional pull and competitive necessity of a ‘guarantee’, we worked closely with stakeholders across both teams to design multi-use, eye-catching iconography that could sit proudly across critical user journeys—think homepage, product pages, and especially beside key conversion triggers like the ‘Add to Cart’ button.

We overcame branding complexity (balancing a diverse colour palette and varied site architecture) by iterating through several design passes, always aligning with brand guidelines and practical display contexts.

Tested, Proven and Rolled Out for Commercial Impact

We ran a comprehensive ABCD test through Convert.com, showing one-quarter of users reach the original website or one of three new designs featuring the Colour Match Guarantee badge in different brand-aligned colours.
By directly comparing each variant, we found the blue and white badge maximised user confidence and stood out just enough to be effective without disrupting the visual hierarchy.

Collaboration between Door4’s CRO analyst, designers, and PaintNuts’ stakeholders ensured every step—creative, technical, and organisational—was aligned, tested and measurable. Upon statistically significant results, the winning design was rolled out sitewide, supported by robust trust messaging.

Measuring Uplift: Data-Driven Results Define Success

Success was benchmarked against two key KPIs: site conversion rate and overall revenue uplift. We tracked user behaviour throughout the test and confirmed a 19% conversion rate increase for the winning badge design.

These results gave both client and Door4 the confidence to expand the trust signal across more customer journeys. Success criteria included both quantitative outcomes (conversion/revenue) and qualitative improvement in perceived trust, which
internal and customer feedback validated.

Unlocking Trust, Growth and Future Performance

By elevating the Colour Match Guarantee to a visible, central role in the UX, PaintNuts regained ground against competitors and proved to customers their confidence in product quality. The uplift in conversion rate directly drove revenue gains, but the long-term value is even greater: a scalable, brand-aligned trust asset that supports future marketing, reduces friction in the buyer journey, and cements PaintNuts’ leadership position.

The business can now confidently iterate on this USP, test further trust signals, and explore new messaging—knowing data-led decisions deliver measurable impact.

PaintNuts is a UK leader in automotive touch-up paint, boasting advanced registration-based matching with record accuracy.

Their Colour Match Guarantee sets the business apart – offering customers a level of assurance the competition can’t equal. However, this guarantee wasn’t leveraged in their customer experience; it was buried deep in terms and conditions, at odds with competitors who featured similar USPs prominently. This underuse meant PaintNuts missed out on lost trust, lost differentiation, and ultimately lost sales.

The business knew it needed to bring this guarantee to the fore, but also grappled with the challenge of doing so without diluting branding, confusing site layouts, or disrupting user experience. The core commercial driver was crystal clear—unlock more revenue and site trust by showcasing an existing, robust promise.

Door4 was chosen for their commercial focus and proven capability in CRO/UX strategy alongside creative, brand-sensitive design.

Door4 brought the Colour Match Guarantee to life by designing multi-use iconography and rigorously validating it via multi-variant CRO testing, all in close partnership with PaintNuts stakeholders.

Our response began with deep competitive insight: a colour match guarantee is one of the strongest trust signals in a commoditised market. Together with PaintNuts, our CRO analyst shaped the initial idea and briefed our designers and developers.

The creative challenge was significant: the iconography needed to be new and stand out, but also respect a diverse brand palette and blend with USP displays across varied website sections. We created and iterated several icon sets and, using Convert.com as our test bed, structured an ABCD test. Each visitor saw either the original site or one of three variants, ensuring robust comparison.

Regular feedback rounds with both Door4’s and PaintNuts’ teams ensured stakeholder alignment at all stages. Once a statistically significant uplift was achieved, the best-performing design was rapidly and confidently rolled out across the site. This staged, feedback-driven process de-risked the creative leap and focused outcomes on commercial proof.

The most compelling business outcome: a 19% increase in site conversion rate triggered purely by the new trust signal.

Headline revenue grew directly in tandem. Key insights from testing showed that trust signals are most effective when they are bold and contextually placed—‘close to the action’ on the site.

Feedback internally and from customers validated that the promise, once visible, became a reason to choose PaintNuts over competitors. The new iconography has since become a strategic asset: adaptable for other trust messaging, supporting wider marketing, and underpinning future CRO improvements. PaintNuts now benefits from a scalable, evidence-backed model for UX improvements that drive tangible ROI.