S/
00/ Portfolio · v2026

SERGIHERRADOR

Backend Software EngineerJavaSpring BootREST APIs

I build reliable backend systems and APIs, turning complex business requirements into clean, maintainable software. Backend engineer by profession. Builder and curious technologist by nature.

View my work→My experience
Sergi's chibi robot mascot
zsh — sergi@barcelona ~ %
› whoami
Sergi Herrador
› role
Backend Software Engineer
› core_stack
Java + Spring Boot
› status
Building reliable software...
›
scroll
01/ About · my journey

From Android apps
to backend systems.

Every chapter kept sharpening the same instinct: build software that actually holds up in the real world. The tools changed, the discipline stayed.

developer.profilelive
Sergi Herrador
id · sh_2026
name
Sergi Herrador
location
Barcelona, ES
role
Backend Engineer
focus
Java + Spring Boot
status
Building reliable software...
// current specialization
Backend Software Engineering
Java · Spring Boot · REST APIs · DDD · Clean Architecture
  1. chapter_01Fundamentals

    Foundations

    DAM · Desarrollo de Aplicaciones Multiplataforma. Academic foundations in software development — first lines of production code, first taste of shipping software.

    academic.record★
    9.42/ 10
    Final average grade · DAM
    outstanding
    perfect scores · 10/1004 / modules
    10[PERFECT_SCORE_MODULE_01]
    10[PERFECT_SCORE_MODULE_02]
    10[PERFECT_SCORE_MODULE_03]
    10[PERFECT_SCORE_MODULE_04]
  2. chapter_02Android · Kotlin

    Mobile builder

    Android · Kotlin · APIs · Firebase · Google Maps. Early specialization and project development in native Android applications.

  3. chapter_03APFutura

    First professional experience

    APFutura — first professional step from academic and Android work into real-world software delivery. Full details in the Experience section below.

    dates[APFUTURA_DATES]
    stack[APFUTURA_TECH_STACK]
  4. chapter_04Current focus

    Backend engineer

    Current professional specialization in backend engineering with Java and Spring Boot at CaixaBank Tech.

02/ Experience

Engineering backend systems in the real world.

current focus
CaixaBank Tech logo
current · full-time

CaixaBank Tech

Backend Software Engineer
Barcelona · ES
  • Design and evolve REST APIs and enterprise backend services on the JVM.
  • Apply Domain-Driven Design, Clean Architecture and Value Objects to shape maintainable code.
  • Translate real business requirements into clean, testable software.
  • Ship in production stacks with Java, Spring Boot, Oracle, Docker and Postman.
Core stack
JavaSpring BootREST APIs
Architecture & data
DDDClean ArchitectureOracle
Tools
DockerPostman
Sergi at CaixaBank Tech
architecture.diagramlayered
APIL1
REST endpoints · Postman contracts
ApplicationL2
Use cases · orchestration
DomainL3
DDD · value objects · invariants
InfrastructureL4
Spring Boot · adapters
DatabaseL5
Oracle · migrations
previous experience
APFutura logo

APFutura

[APFUTURA_ROLE]
previous · role
[APFUTURA_DATES]

[APFUTURA_DESCRIPTION]

Tech stack
[APFUTURA_TECH_STACK]
company.record01
companyAPFutura
role[APFUTURA_ROLE]
dates[APFUTURA_DATES]
stack[APFUTURA_TECH_STACK]
03/ Selected work

Four projects. Four worlds.

featured · 01Android · Ghibli-inspired

SerGhibli

An Android application inspired by Studio Ghibli, built during Sergi's mobile development journey. A love letter to animation, wrapped inside a native mobile experience.

KotlinAndroidREST API
video.reel.mp4[ AUTOPLAY · MUTED ]
View project →View code
02 · TriviaAndroid game

Android Trivia App

A mobile trivia game with multiple rounds, difficulty selection, a countdown timer, image-based questions, score tracking, dark mode and native sharing.

Android Trivia App settings in dark mode
Android Trivia App Cowboy Bebop gameplay question
Android Trivia App perfect score results
[ TRIVIA_VIDEO_PLACEHOLDER ]
KotlinAndroidTimerDark mode
View project →View code
03 · MapsLocation-based · Android

SergiiTB Maps

A location-based Android application built on top of map functionality and geographical data — pins, routes and coordinates as first-class citizens.

41.3874° N · 2.1686° E
KotlinAndroidGoogle MapsGeolocation
[ MAPS_VIDEO_PLACEHOLDER ]
View project →View code
04 · DataODS 7 · Barcelona

Barcelona Energy Consumption

Analysis of electricity consumption in Barcelona by postal code, economic sector and time slot — an academic project tied to SDG 7: Affordable and Clean Energy.

PythonData analysisVisualization
by time slotkWh
[ ENERGY_TIME_SLOT_CHART_PLACEHOLDER ]
by sectortrend
[ ENERGY_SECTOR_EVOLUTION_CHART_PLACEHOLDER ]
by postal code08xxx
[ ENERGY_POSTAL_CODE_CHART_PLACEHOLDER ]
interactive map · barcelonalive_data
[ ENERGY_INTERACTIVE_MAP_PLACEHOLDER ]
postal_codes73
sectors6
time_slots3
themeSDG 7
View project →View code
04/ Tech universe

A stack with a clear center of gravity.

core_expertise · primary/ 08
Java+ Spring Boot
REST APIsDDDClean ArchitectureOracleDockerPostman
> production stack · what pays the rent and keeps systems reliable
Previousprojects · learning
KotlinAndroidJetpack ComposeFirebaseGoogle Maps API
Explorationscuriosity
PythonMachine LearningComputer VisionData Analysis
05/ Contact

Let's build something
reliable.

Got a complex problem? Let's turn it into clean software. Open to backend engineering roles, collaborations and interesting technical conversations.

Say hello →Download CV
email · hello@sergi.devlinkedin · /in/sergi-herradorgithub · @sergiherrador
Mascot waving goodbye
zsh — sergi@barcelona ~ %
› connection_status
ready
› location
Barcelona · ES
› awaiting_next_challenge
...
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