Home/Expertise/Migration & Modernization/Application Modernization
Expertise · Application Modernization

Your applicationsmodernized,without disruption.

Audit, migration plan, and progressive rebuild. We keep what works, replace what doesn’t, without freezing your progress or creating long-term dependencies.

bascule-plan.v2.json
Sprint 06 · active coexistence
Migrated Modules4 / 7 · 57%
ModuleLegacyTargetStatus
AuthenticationSymfony 3 · PHP sessionsSupabase AuthMIGRÉ
Mandate ManagementPHP · legacy MySQLNext.js · PostgreSQLMIGRÉ
Hunter SpaceTwig · jQueryNext.js · ReactMIGRÉ
Client SpaceTwig · jQueryNext.js · ReactMIGRÉ
Admin back-officeSymfony EasyAdminDirectusEN COURS
NotificationsCron PHP · SwiftMailerÀ FAIRE
ReportingManual CSV exportsÀ FAIRE
Coexistence activeUser disruption 0Sprint 06 / 11
01 — Why us

Three principles,
that distinguish modernization from a rewrite.

An application slowing down your business doesn’t need to be discarded. It needs to be read, understood, and rebuilt piece by piece while operations continue.

01

Progressive migration

Old and new systems coexist until full switch-over. Your teams keep working while we modernize. No business interruption, no freeze on ongoing developments.

02

We reuse the existing, we don’t discard it

PHP, Java, .NET, Symfony, legacy Rails, Bubble, Airtable: we audit, extract what holds value, and rebuild what needs to be. No rewriting for the sake of it.

03

Handover to internal teams included

Documentation, code reviews, training. Our goal isn’t to become indispensable. You take back control whenever you want—it’s in scope, not an add-on.

03 — Target stack

What we modernize toward.

Scroll’s standard target stack—modern, maintainable, and recruit-friendly. No exotic tech with no future. The source code returns to you, in your Git, with no permanent dependency on Scroll.

Commonly refactored legacy
PHPSymfonyJava.NETRuby on RailsPythonBubbleAirtableFlutterFlow
Target stack — Scroll

Front

Next.js
React
TypeScript

Back / Data

PostgreSQL
Directus

AI / Agents

Mistral, OpenAI, Claude
MCP
LangGraph

Auth

Supabase Auth
Auth0

Ops / Hosting

OVH, Vercel
Docker
GitHub Actions

Monitoring

Sentry
PostHog
Adaptable target stack based on context: modern Java or Python if your IT team is already using them. The goal isn’t to impose Next.js everywhere—it’s to set a target you can maintain.
04 — Case Study

JeRêveDuneMaison — from a rigid business app to a modern stack.

Mandate management application for property hunters, clients, and administrators. Gradual migration to Next.js + Supabase + PostgreSQL, full documentation, and comprehensive support. Coexistence of old and new systems until the final switch.

Read the full case study
Real Estate · Property HuntingModernization · Legacy → Modern Stack
Rigid business appNext.js + Supabase + PostgreSQL

400+ mandates
managed on the new platform.

Rebuilding critical modules, migrating historical data, training all three roles (hunter, client, admin), and seamless progressive transition without service interruption.

400+mandates managed on the new platform
3modernized business roles — hunter, client, admin
0user disruption during coexistence
Next.jsSupabasePostgreSQLTypeScriptjerevedunemaison.com ↗
05 — Modernization Method

Four steps, no big bang.

A dedicated team from scoping to delivery with a dedicated project manager.

01Audit

The existing system, independently.

System mapping, identification of bottlenecks, technical debt assessment, success criteria. Deliverable: diagnosis + migration plan + estimate. 1 to 3 weeks.

02Plan

The migration plan.

Which modules to keep, which to replace, in what order, with what coexistence. Validation with your IT and business teams before any development. No surprises along the way.

03Rebuild

Module by module.

2-week sprints, delivery by modules. Your users switch over gradually, without disruption. Automated tests and monitoring from the first module in production.

04Transfer

Final switch and autonomy.

Decommissioning of the old system, team training, final documentation. Gradual handover to internal teams if desired — your IT takes back control before the contract ends.

06 — Exit

What you get at the end.

A modernization is only successful if your teams take back control. The source code returns to you, your devs are trained, your legacy subscriptions are canceled. No point of no return.

Source code is yours

TypeScript reviewed, tested, documented. In your Git, under your license. Not a blob exported from a third-party tool.

Data preserved

Historical data recovery, integrity checked, migration documented. User history is never sacrificed.

Teams trained

Training sessions, pair programming, documentation. Your devs take back control before the contract ends. No permanent dependency.

Legacy decommissioned

The old system is gradually phased out, module by module, after each scope’s validated migration. No abrupt shutdown.

07 — FAQ

Frequently asked questions

The most common questions we get during scoping. If yours isn’t here, reach out!

Between 2 and 6 months, depending on the system’s size. The audit provides a firm estimate after 1 to 3 weeks—no blind quotes. A 10-year-old Symfony monolith with 80 tables has nothing in common with an 18-month-old Bubble app; we quote after real mapping, not before.

No. Coexistence of old and new is our default method—never a big bang. Your teams keep working, your users keep using the app, and business evolutions aren’t frozen. Modules switch one by one, after continuous testing.

Gradually decommissioned, module by module, after each scope’s validated migration. No abrupt shutdown. Throughout the migration, old and new systems run in parallel, with explicit routing rules. The last module switches when you’re ready—not before.

Yes, systematically. Co-building, code reviews, training, and pair programming at the end of the mission. Knowledge transfer is part of the scope—not an optional add-on. Our goal isn’t to become essential to your operations: your teams take back control before the contract ends if they wish.

PHP, Symfony, Java, .NET, Ruby, Python, old Node. No-code: Bubble, Airtable, FlutterFlow, WeWeb, Retool. Internal tools: custom ERPs, proprietary back offices, accumulated business scripts. Independent audit in 1 to 3 weeks to assess feasibility before any reconstruction commitment.

This is a dedicated expertise: taking over “vibe-coded” projects. Different logic from historical legacy—not years of accumulated debt, but often missing architectural coherence. See our dedicated Dr Vibe Coding page.

We keep what has business value and works. A data access layer, a robust business rules library, an admin interface that does the job: no reason to discard them. We rarely keep the frontend, almost never the authentication, and always the data. The exact scope is defined during mapping.

That’s precisely why the initial mapping takes 1 to 3 weeks. We identify gray areas, orphaned modules, hidden dependencies, duplicated data—before any delivery commitment. The migration plan explicitly lists residual risks.
Get started

Is your application holding your business back? Independent audit in 1 to 3 weeks.

Contact details
contact@agence-scroll.com
+33 6 48 03 90 27
20 Rue des Taillandiers
75011 Paris
Response within 24 business hours.