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

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#Microservices #Observability #SpringCloud #SpringCloudContract #ContractTesting #Pivotal #MicroInfraSpring #SoftwareEngineering #Programming #MarcinGrzejszczak #JakubPilimon #GOTO

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Marcin Grzejszczak, Java Champion and long-time Spring contributor, shares the origin story of Spring Cloud Contract (originally called Acurest): a typo fix in a microservice API broke production because no clients were notified, exposing the need for consumer-driven contract testing. He explains how contract tests catch breaking API changes automatically, why teams often abandon them (the 'contract champion' problem), and a forward-looking idea to use AI to auto-generate contracts from captured production traffic and validate them against OpenAPI specs. He also discusses his work on the Micrometer Observation API and argues that the missing piece in observability beyond logs/metrics/traces is business and technical context.

A Typo Led to the Creation of Spring Cloud Contract • Marcin Grzejszczak & Jakub Pilimon • GOTO 2026