Introduction For the majority of Booking.com travelers, mobile is the primary channel for researching, planning, and booking trips. Recent data shows that over 80% of travelers rely on a mobile app during the research phase, with more than half of all bookings occurring on mobile devices. Consequently, the Android and iOS platforms are critical to the company’s product strategy; engineering…
Booking.com Engineering
https://medium.com/booking-com-development · 10 posts · history since 2025 · active
5 Jun
8 May
How a seemingly simple AWS API call can silently slow down your CI/CD pipelines Review/co-researcher: Gonzalo Ulla The Mystery It started with a line in one of our team’s CI/CD logs that nobody expected: module.project.module.user_buckets.module.s3_bucket.data.aws_organizations_organization.current: Still reading… [15m10s elapsed] 15 minutes and 10 seconds — just to read organization data. A value that should return in milliseconds was holding up…
19 Feb
This post was originally published internally on May 9, 2025 and has been reworked for a public audience. Authors: Ioannis Androulidakis , Mohammed Gaafar Intro The Database Engineering team at Booking.com is constantly looking for ways to improve database reliability and support scaling our business. In 2025 we completed a major milestone in our effort to modernize our infrastructure: we…
2 Feb
The necessity of imperfection: Designing for distributed ownership in Backstage Imagine an internal engineering platform — tooling that is accessed by thousands of developers every day — where every new feature, every piece of critical functionality, is designed, built and maintained by a different, autonomous team. For years, that was the reality of our internal tooling at Booking.com; a productive,…
3 Jul 2025
Over the past 15 months I have been actively working with LLM’s in my job as a software engineer. I have had many moments where I thought singularity was here, but then almost immediately after I would see the agent fall flat on its face. I have become interested in figuring out when and why these new tools fail, in…
18 Jun 2025
Unlocking the Power of Customization: How Our Enrichment System Transforms Recommendation Data Enrichments How are accurate property prices on Booking.com connected to machine learning that recommends appealing property photos? What about the number of users who have wishlisted a property? And how can developers assess if their recommendation models effectively boost traveler clicks? None of these pieces of information are…
15 Apr 2025
Setting up alerts for metrics isn’t always straightforward. In some cases, a simple threshold works just fine — for example, monitoring disk space on a device. You can just set an alert at 10% remaining, and you’re covered. The same goes for tracking available memory on a server. But what if we need to monitor something like user behavior on…
27 Feb 2025
Scrum, Agile Fitting Scrum for Software Development — Part II Break down stories like a boss and a few more tricks source Many software teams use Scrum, but it comes with challenges. While it originated in software development, its creators made it broad enough to work across industries. The idea? Teams should adapt and improve it while sticking to core…
5 Feb 2025
Okay, yes, the title is a bit clickbaity — but stick with me because this is a real story about SRE work, cost optimization, Golang, and open source. An Introduction and Context I apologize for the clickbait title, but I promise this is a real story that gives you a glimpse into what SREs do daily at Booking.com. It’s based…
24 Jan 2025
Scrum, Agile Make your stand-ups short and concise, focus on value added source Scrum is a framework that gives teams the freedom to build their own processes. Unfortunately, teams often create complex, bloated processes that eat up all their time and leave little room for value-added or improvement work. How often do your daily stand-ups stretch past 30 minutes? Last…