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The history of Rejoose

2010: It all started with Eoptimo

Eoptimo was founded as an IT energy efficiency and reduction consultancy firm, focused on helping Danish companies reduce energy consumption. Over the years, Eoptimo provided consultancy to more than 800 companies, driving over 3,000 energy-saving projects.

By collaborating closely with the Danish Energy Board, Eoptimo became a recognised leader in the field. This also laid the foundation for what would later become the Rejoose energy and carbon database, and the foundation for e.tool.
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2017: The foundation of Rejoose

Rejoose was established as a spinoff from Eoptimo, with the goal of using data to drive IT energy efficiency.
 
The data collection engine and the initial database, which contained 150,000 IT products, were transferred from Eoptimo to Rejoose, laying the groundwork for future innovations.
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2019: The launch of e.tool

Rejoose introduced e.tool, a groundbreaking platform offering insights into IT energy efficiency.
 

By this time, the database had grown to over 500,000 IT products, and Rejoose began attracting customers in Denmark, marking the beginning of its commercial journey.

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2020: Expanding across the Nordics

e.tool expanded its reach to IT resellers throughout the Nordics, significantly broadening Rejoose’s market presence.
 
As the database continued to grow with more IT products and categories, Rejoose became an approved endorser and member of the EU Code of Conduct on Data Center Energy Efficiency, reinforcing its commitment to sustainable IT practices.
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2021: Significant growth and new focus

Rejoose experienced significant growth in its customer base, driven by an increasing demand for carbon data as EU Taxonomy and CSRD regulations came into effect.
 
The product database expanded to approximately 1.5 million items, enriching the data available to customers. Rejoose focsued on evolving its data collection engine to meet the rising need for accurate and comprehensive carbon data. 
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2022: A strategic pivot and new solutions

Rejoose pivoted from offering a reporting tool to providing detailed carbon and energy data on IT products and services.
The launch of e.voice, which delivers carbon data at invoice level, marked a major shift. The first deal was signed just one month after its launch, bringing in numerous new customers and expanding Rejoose’s strategic direction. 
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2023: Major innovations and market expansion

The final version of the e.voice API was launched, enabling customers to go live from day one.
 
Rejoose secured funding from the EU/Danish Innovation Fund to further develop its data collection engine and new platforms.
 
The launch of e.insights and e.hub provided automated carbon data solutions for invoices and advanced data aggregation for reporting. With these innovations, Rejoose began expanding into the Benelux and UKI regions, while the team grew across development, sales, and data quality.
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2024: A transformational year

Rejoose launched the Rejoose Carbon Data Collection Engine and Database v3, containing over 6 million IT products and 900 million data sets, all accessible via API.
 
The launch of the e.product API, which provides data for webshops and quote systems, marked another leap in Rejoose’s evolution. New global partnerships and strategic negotiations positioned Rejoose for continued growth.
 
The team expanded across multiple departments, including development, sales, customer success, marketing, and data quality.
2024 has been a transformative year, with Rejoose setting new industry benchmarks.

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2025: The future

As Rejoose looks to the future, we remain committed to driving innovation and expanding our solutions to support sustainable practices in the IT industry. In 2025, our focus includes:

◊ Expanding our database to over 7 million SKUs, including niche IT equipment and services.

◊ Preparing for the implementation of the EU’s Product Environmental Footprint (PEF) standard.

◊ Introducing additional sustainability metrics beyond carbon data to support comprehensive ESG reporting.

◊ Providing distribution- and transport-specific carbon data to enhance supply chain transparency.

◊ Enhancing our solutions to better meet the needs of IT channel partners and their customers.


These priorities reflect our ambition to stay ahead of industry needs, empower our partners with valuable insights, and support the shift towards a sustainable IT sector.