--- title: Taming Microservice Overload: Our Journey to Modular... description: A solution architect at Port of Rotterdam shares how their system grew from a monolith to 90+ microservices, only to discover they had distributed complexity... canonical: https://daily.dev/posts/taming-microservice-overload-our-journey-to-modular-monoliths-by-mario-klaver-6mr3x3tiy twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Taming Microservice Overload: Our Journey to Modular Monoliths by Mario Klaver | daily.dev og:description: A solution architect at Port of Rotterdam shares how their system grew from a monolith to 90+ microservices, only to discover they had distributed complexity... og:url: https://daily.dev/posts/taming-microservice-overload-our-journey-to-modular-monoliths-by-mario-klaver-6mr3x3tiy og:image: https://api.daily.dev/og/posts/6Mr3x3tIY.png og:image:alt: Taming Microservice Overload: Our Journey to Modular Monoliths by Mario Klaver og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Taming Microservice Overload: Our Journey to Modular Monoliths by Mario Klaver **[Devoxx](https://daily.dev/sources/devoxx)** · 45 min read · 0 upvotes · 0 comments ## Summary A solution architect at Port of Rotterdam shares how their system grew from a monolith to 90+ microservices, only to discover they had distributed complexity rather than solved it. The root cause was poorly defined service boundaries not aligned with business domains. Using event storming, they rediscovered proper domain boundaries and are now migrating to modular monoliths using Spring Modulith — one service per subdomain with bounded contexts as internal modules. The talk covers Spring Modulith's module isolation, inter-module event communication (synchronous and asynchronous), module-scoped testing, and a phased migration strategy using feature flags and shared databases. Key takeaway: boundaries matter more than the number of services, and a modular monolith is often the right intermediate architecture before splitting into microservices. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [The Distributed Monolith Trap \(And How to Escape It\)](https://daily.dev/posts/the-distributed-monolith-trap-and-how-to-escape-it--am21bxegj) · Three Dots Labs · 78 upvotes · 3 comments - [Modular Monolith and Microservices: Modularity is what truly matters](https://daily.dev/posts/modular-monolith-and-microservices-modularity-is-what-truly-matters-alztxj5cq) · Hacker News · 28 upvotes · 1 comments --- Tags: [#microservices](https://daily.dev/tags/microservices), [#domain-driven-design](https://daily.dev/tags/domain-driven-design) [View this post on daily.dev](https://daily.dev/posts/taming-microservice-overload-our-journey-to-modular-monoliths-by-mario-klaver-6mr3x3tiy) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Taming Microservice Overload: Our Journey to Modular Monoliths by Mario Klaver","url":"https://daily.dev/posts/taming-microservice-overload-our-journey-to-modular-monoliths-by-mario-klaver-6mr3x3tiy","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/taming-microservice-overload-our-journey-to-modular-monoliths-by-mario-klaver-6mr3x3tiy"},"datePublished":"2026-04-08T20:28:47.821Z","dateModified":"2026-04-08T20:30:10.691Z","description":"A solution architect at Port of Rotterdam shares how their system grew from a monolith to 90+ microservices, only to discover they had distributed complexity...","image":"https://i.ytimg.com/vi/jHXEIPfp5Ig/sddefault.jpg","thumbnailUrl":"https://i.ytimg.com/vi/jHXEIPfp5Ig/sddefault.jpg","isAccessibleForFree":true,"articleSection":"Devoxx","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Devoxx","logo":"https://media.daily.dev/image/upload/s--6vG797wn--/f_auto,q_auto/v1773648800/logos/devoxx?_a=BAMAMiiu0","url":"https://daily.dev/sources/devoxx"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/taming-microservice-overload-our-journey-to-modular-monoliths-by-mario-klaver-6mr3x3tiy","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"microservices,domain-driven-design","timeRequired":"PT45M","video":{"@type":"VideoObject","name":"Taming Microservice Overload: Our Journey to Modular Monoliths by Mario Klaver","description":"A solution architect at Port of Rotterdam shares how their system grew from a monolith to 90+ microservices, only to discover they had distributed complexity...","thumbnailUrl":"https://i.ytimg.com/vi/jHXEIPfp5Ig/sddefault.jpg","uploadDate":"2026-04-08T20:28:47.821Z","duration":"PT45M","url":"https://api.daily.dev/r/6Mr3x3tIY","embedUrl":"https://www.youtube.com/embed/jHXEIPfp5Ig"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Devoxx","item":"https://daily.dev/sources/devoxx"},{"@type":"ListItem","position":3,"name":"Taming Microservice Overload: Our Journey to Modular Monoliths by Mario Klaver"}]} ```