# Karel Callens

> Karel Callens is the Leuven-based CEO and co-founder of Luzmo, the embedded analytics company formerly called Cumul.io. His consulting and public-sector analytics background led into a business founded in 2015, focused on helping software companies give customers understandable data inside their products. His public writing and interviews cover customer experience, developer flexibility, financing and trustworthy AI analytics.

- **Role:** CEO and co-founder at Luzmo
- **Organizations:** Luzmo (formerly Cumul.io), CSC, FOD Economie / SPF Economie / FPS Economy
- **Education:** Master's in Commercial Engineering (Handelsingenieur / Economics), KU Leuven, Master's in Management of Innovative Organizations, Université catholique de Louvain
- **Known for:** Co-founded the analytics business that became Luzmo., Led Luzmo during its January 2023 €10 million Series A announcement., Presented a five-level customer analytics experience framework at SaaSOpen in March 2023.

## Career timeline

- **Before 2015** — Worked in business intelligence and data visualization at CSC and in big data and analytics at the Belgian federal economy administration; exact role dates not established.
- **2014** — Began developing Cumul.io with Haroen Vermylen in March.
- **2015** — Co-founded Cumul.io, now Luzmo, in Leuven.
- **2016** — Cumul.io platform launched in April and entered imec.istart that month.
- **2017** — An imec profile described Callens as CEO, also responsible for frontend development and design.
- **2019** — Built an Amazon Alexa skill using the company API, later described in his own public post.
- **2023** — Company announced a €10 million Series A in January; Cumul.io rebranded as Luzmo in September.
- **2024** — Published an explanation of the Flex SDK and the tradeoff between ease of use and developer flexibility.
- **2025** — Discussed growth through successive S-curves on SaaSiest in April.
- **2026** — Published a LinkedIn article on deciding whether a dashboard request is worth building, dated January 28.

## Achievements

- Co-founded the analytics business that became Luzmo.
- Led Luzmo during its January 2023 €10 million Series A announcement.
- Presented a five-level customer analytics experience framework at SaaSOpen in March 2023.
- Telenet Kickstart finalist in 2015 and Boost-Me finalist in 2016, as listed on his LinkedIn profile.

## Latest updates

- **2026-01** — LinkedIn lists his January 28 article, “How to decide if a dashboard request is worth building?”
- **2025-04** — Appeared on SaaSiest episode 182, published April 25, discussing successive growth curves and changes to customer focus.
- **2024-11** — Published “Building for developers, SDKs and the future of IT” on November 19.

## Links

- Website: https://www.luzmo.com/
- LinkedIn: https://www.linkedin.com/in/karel-callens-10bb023/
- Twitter/X: https://twitter.com/KarelCallens

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Profile page: https://yespress.io/karel-callens
Published by YesPress — https://yespress.io
Last updated: 2026-10-24