This week I had the pleasure of participating in the apidays NYC conference, and what a first day it had (besides it raining…)!

I spent a good portion of my time at the FINOS booth, connecting with attendees, answering questions, and sharing insights about open source in finance. I also enjoyed a lively booth crawl, exploring the vibrant community of API enthusiasts and innovators.

The day kicked off with opening remarks from apidays CTO Baptiste Parravicini , who reflected on the French roots of the conference and emphasized the importance of engaging with your fellow attendees. He also highlighted apidays’ active efforts to close the gender gap, promote federated events (like Openfinity, AuthCon, Green IO, and more), and expand globally—now spanning 14 locations with 80+ events, 100+ sponsors, 100,000+ attendees, 60,000+ companies, 3,000+ speakers, and over 300,000 community members. A memorable moment: “At apidays, the only place you are allowed to use SOAP is in the RESTrooms.”

Next up was Gartner’s Mark O’Neill , who delivered a keynote on the surprising resurgence of XML—pointing out that modern AIs, including GPT-4.1, tend to handle XML more effectively than JSON. (Highly recommend checking out the GPT-4.1 prompting guide: https://cookbook.openai.com/examples/gpt4-1_prompting_guide.) Mark also introduced the new “Beyoncé Rule”: if you like it, you should put an MCP server around it.

One of the most nostalgic moments was seeing Kin Lane, one of the original apidays presenters, who came equipped with the same binder he used 13 years ago! He took us through the evolution of APIs from Salesforce’s early XML APIs to today, where 83% of internet traffic is API-based. His takeaway: while we say “design-first,” for enterprise-scale governance, it’s often more “code-first.”

I then attended Ryan Day ’s talk on building machine learning APIs using FastAPI and ONNX, and got a glimpse into his new book: https://a.co/d/a2f8rx3. Definitely worth a read for anyone working on ML integrations.

A highlight of the day came from X’s API team, with Evan Dolgow and Christopher S.J. Park showcasing astonishing usage metrics—trillions of API calls and impressions that truly highlight the scale of their platform.

I also caught an insightful session on democratizing open banking titled Stop Calling Community Banks the Long Tail, which ties directly into TraderX and BankerX—topics I’ll be covering during my talk on Day 2.

To close out the day, I joined the Capital One session on API Drift Detection and Data Protection. It sparked ideas on improving versioning and governance across API lifecycles.

TBC with the second day summary.