The Diffblue team had an incredible time at QCon London 2025, where we were Silver sponsors. Over three packed days, we connected with hundreds of software engineers, architects, and technical leaders. From live demos and insightful conversations at our booth to a packed talk, QCon delivered a fantastic opportunity to connect with the software engineering community and show what Diffblue is all about.
Connecting with Developers
Our booth was buzzing throughout the conference. We had the chance to speak with hundreds of engineers, architects, and technical leaders from across industries who were eager to see how Diffblue Cover uses AI to agentically write Java unit tests. Many visitors came with curiosity (and some healthy scepticism!) and left impressed after seeing our product in action during the live demos.
On Day 2, Animesh and I were dual-demoing on both of our screens to show the product to as many people as possible. Nonstop action, and we loved every minute of it.
It was fascinating to hear the different challenges teams are facing with testing, code coverage, and the limitations they’ve run into using LLM-based tools for these problems. We really enjoyed showing how Diffblue’s reinforcement learning-based approach helps teams accelerate and improve software delivery.
A huge thank you to everyone who stopped by to ask questions, share stories, and see our demos.
Swag & (The Mandatory) Conference Prize Draw
Of course, no conference experience is complete without swag and we brought some good ones. Our T-shirts and tote bags were a hit, but the overwhelming favourite? Our amazing Diffblue metal water bottles (I’m sipping from mine as I write this blog!). We gave away hundreds, and they seemed to pop up in hands and on tables all over the venue by the end of Day 3.
We also ran a prize draw on the final day with some fantastic giveaways: a LEGO Pac-Man arcade set and a pair of AirPods Max. The draw drew a massive crowd to the booth, and the energy was electric. Soyeb was the lucky winner of the LEGO Pac-Man set, but our AirPods winner wasn’t at the booth to claim their prize. We gave them until the next break to come forward… but no luck. So, we re-ran the draw during the next break, and this time Antoine walked away with the AirPods Max. Congrats again!
Live on Stage: Animesh Mishra’s Talk & Demo
The highlight for us was Animesh Mishra’s talk on Day 2, where he dove into the power of reinforcement learning in code generation and showed how Diffblue Cover can generate meaningful, human-readable unit tests in seconds. The live demo went down a storm and sparked a lot of interest and follow-up conversations afterward.
If you missed it, don’t worry! We’ll be sharing a recording soon.
Drinks, Networking & More
QCon is always more than just talks and booths. The drinks receptions at the end of Days 1 and 2 were the perfect way to unwind and continue conversations in a more relaxed setting (I particularly enjoyed the bao buns on Day 1). And before the closing keynote on Day 3, the final reception brought everyone together one last time to reflect on what was a truly inspiring event.
See You Next Time!
A huge thanks to the organizers of QCon London for putting together such a well-run conference. We were proud to be a sponsor this year and loved engaging with so many passionate technologists.
If you didn’t get a chance to see Diffblue in action at QCon or want a more in-depth look, get in touch to try Diffblue Cover yourself.
We’ll see you at the next one!
Final Thanks
Huge shoutout to the amazing team who made our presence at QCon such a success. The booth was staffed over the three days by myself (Samprit Bains), Indy Hulait, Sulaiman Durrani, and Animesh Mishra.
Behind the scenes, Zoe Laycock expertly planned the whole thing and kept everything running smoothly on the ground (we nearly didn’t have a banner but Zoe saved the day!).
And a big thank you to our amazing engineering teammates Morgan Mazer, Yu Zhong, and James Hamilton, who attended as participants but jumped in to chat with visitors and demo the product like pros. You all made the booth something special.
P.S. Help us settle a debate: we couldn’t agree on the best cookies provided during the event: milk chocolate, white chocolate, or double chocolate? (I voted for milk chocolate.)
