Building Microservices Designing Fine Grained Systems

This interview was recorded for GOTO Unscripted. #GOTOcon #GOTOunscripted https://gotopia.tech Marcin Grzejszczak - Software Engineer at HeroDevs & Java Champion @marcingrzejszczak1716 Jakub Pilimon - Software Architect at jPilo & Software Consultant at Bottega IT Minds @JakubPilimon ORIGINAL TALK TITLE The Typo That Broke Production — And Accidentally Created Spring Cloud Contract RESOURCES Marcin https://bsky.app/profile/toomuchcoding.com https://mastodon.social/@toomuchcoding@fosstodon.org https://twitter.com/MGrzejszczak https://github.com/marcingrzejszczak https://www.linkedin.com/in/marcin-grzejszczak-15565119 https://toomuchcoding.com Jakub https://twitter.com/JakubPilimon https://github.com/pilloPl https://www.linkedin.com/in/jakub-pilimon-449b7984 http://pillopl.github.io Links https://toomuchcoding.com/post https://martinfowler.com/articles/consumerDrivenContracts.html https://www.tomakehurst.com https://youtu.be/9w6YeNNJLkg https://youtu.be/PXKICIiXEUM https://youtu.be/-OUm8BJR7Fg https://youtu.be/l1tyfb5we7I https://youtu.be/GBTdnfD6s5Q https://youtu.be/JcBfnaojcsI https://youtu.be/XCItVwAZl_I https://youtu.be/GPEZWicyZSM https://youtu.be/yNgaU_X8jdw https://youtu.be/mUTx61t443A https://youtu.be/6ndAWzc2F-I https://youtu.be/hDTHcxmoBbQ https://youtu.be/WpvmRaHEQzA https://youtu.be/1PJM8p-RMsY DESCRIPTION In this GOTO Unscripted episode, Jakub Pilimon sits down with Marcin Grzejszczak — Java Champion, Spring Cloud Contract contributor, author, mentor, and founder of a rural housewives' circle (yes, really) — to trace a 15+ year career that went from C++ on the Côte d'Azur to becoming one of the key architects of Spring Cloud Contract and the Micrometer Observation API. Marcin shares how real production pain — a junior dev fixing a typo in an API that silently broke every client — gave birth to what would become Spring Cloud Contract, and how he's never shy about calling out his own embarrassing code (complete with a Javadoc that opens with "I'm sorry"). The conversation pivots sharply into 2025 territory, with Marcin sketching out an AI-powered future for contract testing: instead of manually writing contracts (which developers routinely abandon), capture live production traffic, let AI generate the contracts, and let humans do what they're actually good at — reviewing and approving. Wrapping up with observability, Marcin argues the most underrated pillar isn't logs, metrics, or traces — it's context. Without knowing why something happened (a deployment, a business event), raw telemetry data is just noise. Practical, honest, and occasionally self-deprecating: a thoroughly human conversation in the age of AI. TIMECODES 00:00 Intro 01:19 From Côte d'Azur to Spring Cloud 05:21 Building micro-infra-spring & getting hired at Pivotal 10:30 Spring Cloud Contract: Born from a real production disaster 19:12 Can AI finally make contract testing scale? 27:04 The missing pillar of observability: It's not logs or traces 29:32 Outro RECOMMENDED BOOKS Marcin Grzejszczak • Mockito Cookbook • https://amzn.to/4rXOrtf Marcin Grzejszczak • Instant Mockito • https://amzn.to/4lV2ePQ Sam Newman • Building Microservices • https://amzn.to/3dMPbOs Sam Newman • Monolith to Microservices • https://amzn.to/2Nml96E Roy Osherove • The Art of Unit Testing • https://bit.ly/3obiKNB Charity Majors, Liz Fong-Jones & George Miranda • Observability Engineering • https://amzn.to/38scbma https://bsky.app/profile/gotocon.com https://twitter.com/GOTOcon https://www.linkedin.com/company/goto- https://www.instagram.com/goto_con https://www.facebook.com/GOTOConferences #Microservices #Observability #SpringCloud #SpringCloudContract #ContractTesting #Pivotal #MicroInfraSpring #SoftwareEngineering #Programming #MarcinGrzejszczak #JakubPilimon #GOTO CHANNEL MEMBERSHIP BONUS Join this channel to get early access to videos & other perks: https://www.youtube.com/channel/UCs_tLP3AiwYKwdUHpltJPuA/join Looking for a unique learning experience? Attend the next GOTO conference near you! Get your ticket at https://gotopia.tech Sign up for updates and specials at https://gotopia.tech/newsletter SUBSCRIBE TO OUR CHANNEL - new videos posted almost daily. https://www.youtube.com/user/GotoConferences/?sub_confirmation=1