The Evidence Synthesis Hackathon (ESH, www.eshacakthon.org) was established in 2017, and has now convened 4 physical events and a series of online projects throughout the pandemic. The organisation aims to produce and develop tools and frameworks to maximise accessibility, transparency and rigour of evidence syntheses. Much of the work centres around the use of R to design bespoke, freely available tools, but its remit includes non-coding frameworks and user-interface design. ESH has been responsible for the development of several highly-used tools, including robvis for visualising risk of bias (https://www.riskofbias.info/welcome/robvis-visualization-tool), citationchaser for forwards and backwards citation chasing (https://estech.shinyapps.io/citationchaser/), and PRISMA2020 for producing PRISMA-compliant flow diagrams (https://estech.shinyapps.io/prisma_flowdiagram/). These tools are used by tens of thousands of people each month, contributing a considerable potential efficiency saving and improvement in conduct/reporting quality. This presentation will introduce ESH, its practices and key outputs, and will highlight the components of projects that we believe have contributed to their success. We suggest that these methods should be optimised across ‘evidence synthesis technology’ to not only support improvements in efficiency, transparency and rigour, but also to work towards accessibility and equity in an otherwise sometimes Global-North-biased technological landscape.