A former rail industry business analyst who walked away from the corporate world to confront one of sustainability’s biggest problems has now built a fast-growing verification platform helping organisations prove their environmental claims are real.
Callum Miller spent years analysing rail sector operations before founding ethy, a sustainability SaaS platform that now supports hundreds of businesses across nearly a dozen industries.
He says the vast majority of companies still struggle to tell the difference between genuine impact and well-packaged marketing spin.
The four-year-old company generates between £100,000 and £500,000 in annual revenue by verifying ESG claims and helping responsible brands communicate their impact transparently.
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“A combined interest in sustainability personally and technology professionally led me to found ethy,” Callum told Founder Insights.
“Since about 20 years old, I’ve maintained a passion for responsible living and the idea that businesses should play an active role in driving positive change.
“At the same time, my background in tech made me aware of how powerful digital tools can be in solving real world problems.”
The spark came during a conversation with a co-founder friend working in a similar niche.
Callum said: “We were talking about how difficult it was becoming for consumers to distinguish between genuine sustainability efforts and marketing noise, and how many responsible businesses struggled to communicate their impact clearly.
“That discussion planted the seed for what eventually became ethy.
“At the same time, I realised I didn’t want to spend my career in the corporate world.
“I wanted to take a risk and see how far I could go on an entrepreneurial pathway.”
ethy verifies sustainability and ESG claims for businesses and helps them communicate those claims transparently to customers through industry-backed standards and visual ecolabels.
The platform predominantly supports SMEs, with some enterprise level clients, engaging almost a dozen industries from retail to travel to technology.
But the early years tested Callum’s resolve.
“Managing in London on a shoestring salary in the early years was extremely challenging,” he said.
“I was able to overcome this period — just! — by minimising all expense, sharing an apartment with several other housemates and having practically no social life.
“My partner at the time was also a great support.”
His first customers came through remarkably direct outreach.
Callum said: “I used to message new Instagram followers to thank them, ask about their sustainability goals and share what I was building.
“Those conversations led to our first clients and helped me understand what businesses actually needed, and also helped to shape our product.”
The turning point came when larger, more established brands began reaching out to ethy rather than the other way around.
“It was the moment I realised the problem we were solving was real and starting to become recognised in the market,” Callum said.
The founder describes his biggest challenge as dealing with constant uncertainty.
“There is no playbook, and you are constantly making decisions with very limited information,” he said.
“Learning to stay focused and keep moving forward, even when things feel unclear, has been the hardest part.”
One early mistake proved particularly instructive.
“Probably trying to do everything at once,” Callum said.
“I quickly learned that trying to be a one-man band is unsustainable and inevitably leads to burnout.
“I learnt to trust others and provide ownership across different functions of the business.”
Running ethy has transformed him both personally and professionally.
Callum said: “It has made me far more resilient and thick skinned.
“It has forced me to become better at prioritising, communicating and trusting my instincts.
“Personally, it has also made me more self aware and comfortable stepping outside my comfort zone.”
When asked about his leadership approach, Callum describes it as practical.
“I try to make decisions based on what genuinely moves the business forward, not just what looks impressive on paper,” he said.
His partner has been crucial throughout the journey, supporting the venture both financially and emotionally from day one.
“She has supported the venture from day 1 and even helped name the business,” Callum said.
Looking ahead, Callum’s mission is clear: incentivising positive change in business clients.
“Nothing motivates me more than seeing ethy inspire a company to improve its practices for the sake of people and the planet,” he said.
“The biggest reward is seeing that the work actually influences behaviour.
“Knowing that a business has improved its practices because of something we built is incredibly motivating.”
Despite the challenges of economic uncertainty in the UK and watching many businesses fail, Callum takes pride in one particular milestone.
“I’m proud that we still have an operational business after 4 very testing years, especially given the economic uncertainty in the UK and the number of great businesses that have unfortunately gone under,” he said.
