Monolith to microservices migration case study at Hygge Software

Country Navigator: Ten Years of Platform, Rebuilt Without Going Dark

A cultural intelligence training platform serving large enterprises worldwide had no tests, no CI/CD, and processes that lived in one person's head. Hygge rebuilt it into services and moved everyone across without a single window of downtime.

Ready to Modernize Without Going Dark

Ten years of platform and an enterprise user base that cannot be interrupted. Hygge scopes that rebuild the way this one ran.

What the Cultural Intelligence Training Platform Does

What platform modernization services changed under a platform its users were never asked to stop using.

Service-Oriented Rebuild

A MACH-aligned architecture with an Angular headless frontend and NestJS microservices behind an API gateway, replacing a monolith that had grown for a decade.

Zero-Downtime Migration

The full user base and content moved from legacy infrastructure to modern cloud with no interruption, because enterprise customers do not schedule outages around their vendor.

Database Migration

A staged schema and data migration from MS SQL Server to MySQL, planned so the cutover was a step.

Enterprise SSO on Keycloak

SAML single sign-on rebuilt on Keycloak, replacing manual per-client metadata exchange that only worked because one person remembered how.

Observability From Zero

Prometheus, Grafana and Sentry across every service, on a platform that previously had no way to see what it was doing.

Production AI Assistant

A fine-tuned open-weight model with retrieval over a curated knowledge base and text to speech, with each organization getting its own isolated knowledge base and prompt configuration.

The Challenge

A decade-old monolith with no automated tests and no CI/CD, running critical processes that existed only as tribal knowledge. Certificate renewal and SSO onboarding worked because specific people remembered the steps. The user base made every option harder. Large enterprise customers were using the platform daily, so downtime was a thing that could not happen.

The platform also had no AI capability and could not scale to the content and localisation growth the business was planning.

Our Solution

Hygge rebuilt the platform into a service-oriented architecture and moved users and content across in stages, so the migration never had a moment where the old system was gone and the new one was not ready. SSO moved onto Keycloak with SAML, turning a manual per-client process into a standard one. Terraform and Docker put the infrastructure into code, and Prometheus, Grafana and Sentry gave the team a view of a system they previously operated blind.

The AI assistant runs on a fine-tuned open-weight model with retrieval over curated content, isolated per organization, so one customer's knowledge base never reaches another's users.

Results

What a decade of corporate training software development left behind, and what the platform does now.

0

Downtime Moving a Decade-Old Platform

1 config

Replaces the SSO Setup Only One Person Knew

1 per org

Isolated AI Knowledge Base for Each Enterprise

10 years

Of Monolith Rebuilt Into Services

The Stack Behind the Zero Downtime Migration

Angular

TypeScript

NestJS

MySQL

Keycloak

AWS

Terraform

Docker

Kubernetes

Prometheus

Grafana

Sentry

LoRA

QLoRA

Stripe

Services Involved

Legacy Modernization Software Architecture Cloud Migration RAG Development System Integration

HUGE compliments team - LPv2 are looking truly AWESOME!!!!-Hans van der Linden.
David Handel
CEO & Co-Founder

From Monolith to Partnership

Step 1 - Service Boundaries

The decade-old monolith mapped and split into services that could be built, deployed and scaled on their own.

Step 2 - Infrastructure as Code

Infrastructure moved into Terraform and Docker on AWS EKS, with CI/CD established where none had existed.

Step 3 - Front End and Services

An Angular headless front end and NestJS services built out behind it, replacing the monolith screen by screen.

Step 4 - Database Migration

Records moved from MS SQL Server to MySQL, with the old and the new reconciled before anything switched over.

Step 5 - Zero-Downtime User Migration

The full enterprise user base and content moved across in stages, with no disruption for a customer at any point.

Step 6 - Enterprise SSO

Single sign-on rebuilt on Keycloak and SAML, replacing manual metadata exchange with every client.

Step 7 - Observability From Zero

Prometheus, Grafana and Sentry across every service, on a platform that previously had no monitoring at all.

Step 8 - Production AI Assistant

A fine-tuned open-weight model with retrieval and text to speech, grounded in the platform's own content and isolated per organization.

Step 9 - AI-Assisted Content Refresh

The country and culture guides refreshed with optional audio narration, so the library stayed current without a manual rewrite.

Track Record

Company-wide numbers, built from every project Hygge has delivered since 2019.

7 years

in continuous production engineering and AI delivery since 2019

200 +

end-to-end projects shipped for clients since 2019

3

independent quality and security certifications

Where Platform Modernization Services Pay Off

Industries that share the shape of the problem Country Navigator solved: a decade-old platform enterprise customers depend on daily, a rewrite that happens underneath them, and a migration with no window to take the system down.

All Hygge Industries

EdTech

Learning platforms that have to work for years, carry real enterprise customers, and add AI without teaching anyone something false.

Explore the industry

HR & Recruitment

Hiring platforms, professional networks and staffing marketplaces where matching runs on structured data.

Explore the industry

Aviation

Operations, maintenance and training software for an industry where every system carries a regulatory shadow.

Explore the industry

Healthcare & Staffing

Marketplaces and workflow tools for care organizations, where the mechanism in the middle decides whether the market is fair.

Explore the industry

Solutions Built Into Country Navigator

A decade-old monolith became three Hygge products running side by side, and a zero downtime migration kept the enterprise customers on it working through the whole move.

All solutions

LMS & eLearning Platform Development

Assessment and cross-cultural learning delivered to enterprise cohorts, with a production AI assistant grounded in the material belonging to that organization.

Open the solution

1 per orgAn isolated AI knowledge base for each enterprise
10 yearsOf course and assessment content carried forward
0 downtimeWhile the user base moved to the new platform

Customer & Partner Portal Development

Each enterprise gets its own space: single sign-on against the identity provider they already run, their own administrators, and their own view of who has completed what.

Open the solution

1 configReplaces an SSO setup only one person knew
Per orgData, admins and reporting kept apart
Self-serveAdministrators manage cohorts without a ticket

API & Payment Integration

The monolith was cut into services that talk over documented interfaces, so a release to one part stops being a release to all of it.

Open the solution

10 yearsOf monolith rebuilt into services
1 contractEach service reached through a documented interface
0 downtimeThrough the migration, with live users on it

More Products Hygge Has Shipped

Projects that share the same shape of problem as this cultural intelligence training platform: a decade-old system enterprise customers depend on daily, and corporate training software development that has to keep serving them mid-rebuild.

All Hygge Case Studies

Professional Networking

BoardsOnline

A founder had paid for a platform that reports said was finished. An audit showed what worked, and the rebuild started from there.

3 bucketsSorted features a status report called done
~6 monthsFrom that audit to a stable platform
1+ yearOf support past the original contract

Read the case

Platform Modernization Services: Frequently Asked Questions

Frequently asked questions about monolith to microservices migration case study

How do you migrate an enterprise user base with no downtime?

In stages, with the old and new systems both live during the transition. Nothing about the migration required a moment where the platform was unavailable, which is the only acceptable answer when the customers are enterprises using it daily.

Why rebuild the monolith?

Ten years of growth with no tests, no CI/CD and undocumented operational processes meant every change carried unknown risk. The rebuild was about making future work predictable, not about the architecture being unfashionable.

Why a fine-tuned open-weight model for the AI assistant?

Because each organization needs its own isolated knowledge base and prompt configuration, and the answers have to stay grounded in the platform's curated content. Fine-tuning with LoRA and QLoRA on top of retrieval gave that control without a per-call dependency on an external provider.

What does the partnership cover now?

Five concurrent workstreams, running since late 2024, spanning the platform itself, the AI assistant, learning module work, infrastructure and content. It began as a scoped rebuild and became a standing project.

Let's Build Something That Matters

We're your one-stop Digital Engineering Partner - tell us the process, product, or data problem you're trying to solve, and Hygge scopes AI and software work around a business result before any code gets written.

Tell Us What You're Building

Share the product, process, or data problem behind the request, along with the systems, data, or timeline the build has to work around.

Get an Audit-Backed Consultation

Hygge reviews the systems and data behind the request before the first call, so the conversation opens with real specifics already on the table.

Receive a Scoped Proposal

A plan with the approach, team, timeline, and cost, built around the business result the project needs to hit.