The Typo That Broke Production — And Accidentally Created Spring Cloud Contract • Marcin Grzejszczak & Jakub Pilimon
GOTO - The Brightest Minds in Tech
Embarrassing code and refactoring lessons
Marcin admits a messy JSON-to-JSONPath class, modelling sessions, AI refactors and open source feedback benefits.
This interview was recorded for GOTO Unscripted.
https://gotopia.tech
Marcin Grzejszczak - Software Engineer at HeroDevs & Java Champion
Jakub Pilimon - Software Architect at jPilo & Software Consultant at Bottega IT Minds
ORIGINAL TALK TITLE
The Typo That Broke Production — And Accidentally Created Spring Cloud Contract
Check out more here:
https://gotopia.tech/articles/435
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
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.
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
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