Introduction
Chapter
ANTWERP, BELGIUM
10th OCTOBER 2025
Architecture
Chapter
{}
Domain
Controller
Persistence
Adapter
Adapter
SPI
API
Adapter
Adapter
to the rescue!
Alistair Cockburn's pattern
SPI
API
Controller
Persistence
Domain
{}
Domain
Controller
Persistence
Adapter
Adapter
SPI
API
Domain
Chapter
{}
Engine
Time Circuit
Tank
TimeStamp
Fuel
Liter
Miles
Per Hour
Time Jump
Nuclear Reactor
Delorean
Plutonium Pellet
Flux Capacitor
GigaWatt
DeLorean
Time Circuit
Flux Capacitor
Flux Capacitor
Time Circuit
Nuclear Reactor
DeLorean
Flux Capacitor
Plutonium Pellet
Nuclear reactor
GigaWatt
Plutonium Chamber
Nuclear Reactor
Engine
Tank
Miles
Per
Hour
Fuel
Liter
Time Jump
Flux Capacitor
TimeStamp
Time Circuit
Time Circuit
Time Circuit
Flux Capacitor
Target Vision
Flux Capacitor
DeLorean
Nuclear Reactor
Flux Capacitor
Time Circuit
Flux Capacitor
Nuclear
Reactor
Timecircuit
DeLorean
BACK«
DISTRIBUTED EDITION
TO
THE
BBOM
Flux
Capacitor
why not rushing?
Design uncertainty
Mistakes are expensive
No clue on what to extract
Modular Monolith
Strategy
First Hexagon
Chapter
DeLorean
Flux Capacitor
Nuclear Reactor
Time Circuit
Time Jump
Engine
Miles
Per
Hour
Fuel
Liter
Flux Capacitor
Tank
Plutonium Chamber
Plutonium Pellet
Nuclear reactor
GigaWatt
Time Circuit
TimeStamp
DeLorean
Flux Capacitor
Plutonium Pellet
Nuclear reactor
GigaWatt
Plutonium Chamber
Nuclear Reactor
Engine
Tank
Miles
Per
Hour
Fuel
Liter
Time Jump
Flux Capacitor
TimeStamp
Time Circuit
Time Circuit
Time Circuit
Flux Capacitor
DeLorean
Flux Capacitor
Nuclear Reactor
Time Circuit
Time Jump
Engine
Miles
Per
Hour
Fuel
Liter
Flux Capacitor
Tank
Plutonium Chamber
Plutonium Pellet
Nuclear reactor
GigaWatt
Time Circuit
TimeStamp
Plutonium Chamber
Plutonium Pellet
Nuclear reactor
GigaWatt
Nuclear Reactor
Time Jump
Engine
Miles
Per
Hour
Fuel
Liter
Flux Capacitor
Tank
Time Circuit
TimeStamp
DeLorean
Vertical Slicing
Chapter
Controller
persistence
DB
DeLorean
persistence
Controller
DB
DeLorean
Nuclear
Reactor
persistence
Controller
DB
DeLorean
Nuclear
Reactor
persistence
Controller
persistence
DB
DeLorean
Nuclear
Reactor
Controller
persistence
Controller
2 microservices
with their
2 microservices
persistence
DB
DeLorean
Nuclear
Reactor
Controller
persistence
Controller
DB
DB
DB
DeLorean
Nuclear
Reactor
Controller
persistence
persistence
Controller
Ports & Adapters
Chapter
DB
SPI
Nuclear
Reactor
REST
API
DB
SPI
Delorean
REST
API
SPI
Delorean
Nuclear
Reactor
REST
Client
Ports & Adapters
Nuclear
Reactor
Delorean
API
to the rescue!
SPI
Inspired by Alistair Cockburn's pattern
Port
Adapter
Client
REST
INPROC
DB
SPI
Nuclear
Reactor
REST
API
DB
SPI
Delorean
REST
API
SPI
DB
SPI
Nuclear
Reactor
REST
API
DB
SPI
Delorean
SPI
API
INPROC
Anticorruption layer
INPROC (infrastructure)
SPI
API
GigaWatts
M Horse
Power
GigaWatts
NuclearReactorAdapter
(impl)
GeneratePower
ACL
Domain
Domain
Delorean
Nuclear Reactor
M Horse
Power
NuclearReactor
Hived Modular Monolith
Chapter
Fuel
Liter
Flux Capacitor
Tank
Engine
Miles
Per
Hour
Time Jump
Time Circuit
Time
Stamp
Plutonium Chamber
GigaWatt
Nuclear reactor
Plutonium Pellet
DeLorean
Time Circuit
Nuclear Reactor
Nuclear Reactor
DeLorean
Flux Capacitor
Time Circuit
Plutonium Chamber
Plutonium Pellet
Nuclear reactor
GigaWatt
Time
Stamp
Time Circuit
Engine
Miles
Per
Hour
Tank
Fuel
Liter
Time Jump
Flux Capacitor
Nuclear Reactor
DeLorean
Flux Capacitor
Time Circuit
Engine
Tank
Miles
Per
Hour
Fuel
Liter
Flux Capacitor
Time Jump
Plutonium Chamber
Plutonium Pellet
Nuclear reactor
GigaWatt
Time
Stamp
Time Circuit
DeLorean
Flux Capacitor
Plutonium Pellet
Nuclear reactor
GigaWatt
Plutonium Chamber
Nuclear Reactor
Engine
Tank
Miles
Per
Hour
Fuel
Liter
Time Jump
Flux Capacitor
TimeStamp
Time Circuit
Time Circuit
Flux Capacitor
Time Circuit
Modularization Strategy
Nuclear
Reactor
DeLorean
Time
Circuit
Flux
Capacitor
?
?
?
?
Scale-out
Chapter
cpu usage
50%
25%
75%
Nuclear
Reactor
DeLorean
Time
Circuit
Flux
Capacitor
50%
25%
75%
Nuclear
Reactor
DeLorean
Flux
Capacitor
Time
Circuit
cpu usage
ACL
SPI
DB
SPI
INPROC
REST
API
delorean
DB
SPI
nuclear
reactor
API
ACL
SPI
DB
SPI
INPROC
REST
API
delorean
API
DB
SPI
REST
nuclear
reactor
1
ACL
SPI
DB
SPI
INPROC
REST
API
delorean
API
DB
SPI
REST
nuclear
reactor
2
1
ACL
SPI
DB
SPI
CLIENT
REST
API
delorean
API
DB
SPI
REST
nuclear
reactor
2
API
DB
SPI
REST
ACL
SPI
DB
SPI
CLIENT
REST
API
delorean
nuclear
reactor
µ
nuclear reactor
µ
delorean
3
HTTP
DeLorean
Flux Capacitor
Time Circuit
Nuclear Reactor
DeLorean
Flux Capacitor
Time Circuit
Nuclear Reactor
Test Slicing
Chapter
YOUR Test Suite may be
a hidden monolith...
Production code
TESTS
The hidden Monolith
Production code
TESTS
Tests must be modularized
Production code
TESTS
with the same level of quality as the production code
stubs
stubs
stubs
Conclusion
Chapter
Microservices-ready
Modular Monolith
a fractal pattern
Controller
API
Nuclear
Reactor
SPI
persistence
DB
persistence
Controller
DB
SPI
API
DeLorean
INPROC Ports & Adapters
Controller
API
Nuclear
Reactor
SPI
persistence
DB
API
persistence
Controller
DB
SPI
API
DeLorean
InPROC
SPI
INPROC Ports & Adapters
InPROC
SPI
persistence
Controller
DB
SPI
API
DeLorean
API
Controller
API
Nuclear
Reactor
SPI
persistence
DB
Julien Topçu
Thomas Pierrain
@tpierrain.bsky.social
@Julientopcu.com
Live Coding The Hive: building a microservices-ready modular monolith
By Julien Topçu
Live Coding The Hive: building a microservices-ready modular monolith
After a decade, the industry has realized that poorly designed microservices can easily turn into a distributed monolith, often more problematic than the spaghetti monolith they aimed to address. To tackle this issue, the concept of a modular monolith is emerging as an alternative approach. However, the challenge still lies in effectively splitting it without falling into the pitfall of tightly coupled modules. The Hive pattern helps you build a microservices-ready modular monolith, by leveraging multiple hexagonal architectures and vertical slicing, each module is loosely coupled and ready to be extracted as a separate service. During this live coding session, we will begin with a legacy spaghetti monolith and migrate it step-by-step to a Hived modular monolith, wrapping up with a demonstration of extracting a module and transforming it into a separate micro-service.
