Legacy Rails takeover · Rails 8 migration

Rails upgrade services Take over your legacy Rails app and bring it to Rails 8 without breaking it.

Your application still runs on Rails 4, 5 or 6, the developer who built it has moved on and nobody dares touch the code. Our Rails upgrade service takes the app over, secures it with tests, then moves it one version at a time to Rails 8 while your business keeps running on it.

Talk about my application How the upgrade works
  • 100+ projects delivered
  • 8 years of experience
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What's included

What our Rails upgrade services include

A Rails application without a developer does not collapse overnight. It falls behind: gems stop receiving fixes, your host drops your Ruby version and every small change becomes a risk. Here is what a takeover and upgrade by our Ruby on Rails agency covers.

Takeover audit

We review the code, the database schema and the infrastructure, list your Rails, Ruby and gem versions, and pinpoint known vulnerabilities and fragile areas. You get a clear assessment and an action plan priced step by step.

A test safety net first

Inherited apps often have few or no tests. We start by writing RSpec tests for the critical flows, such as sign-in, ordering, invoicing and exports. They guard every step of the upgrade.

Version by version

We move from one minor version to the next and never jump straight from Rails 5 to Rails 8. Each step handles its own deprecations and new defaults, then goes to production before the next one.

Dependencies and security

Gems updated, abandoned ones replaced, vulnerabilities flagged by bundler-audit and Brakeman fixed. PostgreSQL and Node are upgraded too when the application depends on them.

Targeted modernisation

Once the app is current, some projects start to pay off: Hotwire instead of jQuery, Solid Queue instead of Sidekiq and Redis, deployment with Kamal. We only suggest them when the benefit is real.

After the upgrade

We can stay responsible for the application through regular updates, security patches and new features, so it never falls this far behind again.

Why now

Why a Rails 8 migration should not wait

Rails versions that no longer receive security patches leave your application exposed, and every month of delay adds more deprecations to handle and more gems to replace. The gap compounds: an app two versions behind is a project, an app five versions behind is a much bigger one. Hosting platforms also retire old Ruby versions, which can force an emergency migration at the worst possible moment.

There is a hiring cost too. Developers want to work on current Rails, and a legacy app makes every recruitment harder. Bringing it up to date is often what makes it possible to grow the team again.

These are the signs we see most often when a client asks us to take over a legacy Rails app.

Nobody has touched it in months

The original developer or agency is gone, the documentation is thin and the team is afraid that any change will break production.

The logs are full of warnings

Deprecation warnings, gems pinned to old versions and security alerts from your repository host that no one acts on.

The platform is pushing you out

Your host or a key gem is dropping support for your Ruby or Rails version, and the deadline is set by someone else.

Our method

How a Rails upgrade works

Four steps, designed to keep your application online and your team informed throughout.

  1. Access recovery and audit Git repository, servers, database, third-party accounts: we gather everything, which is often what is missing once the developer has left. We get the app running locally, then deliver the audit with risks, priorities and a quote for each step.
  2. Tests and continuous integration Tests for the features your revenue depends on, and continuous integration to run them on every change. Urgent security holes are fixed straight away.
  3. Dual-boot upgrade With a second Gemfile, the app boots on the current version and the next one in parallel. We fix deprecations until the tests pass on both, switch production over, and repeat up to Rails 8 and Ruby 3.4.
  4. Modernisation and maintenance Once current, we carry out the modernisation you have approved. The application then moves into maintenance: regular updates, monitoring and new features.

Target version

The target stack: Rails 8 and Ruby 3.4

We aim for the latest stable Rails and Ruby, with tools you could hand to any Rails developer tomorrow.

Tests first

Tests are what let us move fast without breaking things. They stay in the project afterwards and protect every future change.

Hotwire instead of an ageing front end

Turbo and Stimulus replace jQuery or an abandoned JavaScript framework, with much less code to maintain.

Fewer services to run

Background jobs run through PostgreSQL, so Redis often becomes unnecessary: one less service to host and monitor.

Out of locked-in hosting

If your platform is dropping support for your stack, Kamal deploys the app to a standard server with a documented procedure.

Case study · a Rails app looked after for the long run

Le Baroudeur du Vin: a business tool that has to keep up

Le Baroudeur du Vin is an online wine shop. We designed its e-commerce site and SEO strategy, then built its internal OS in Ruby on Rails, the tool that runs the business day to day. A tool like this lives for years and has to keep pace with Rails and Ruby releases without ever holding up an order.

Stack
Ruby on Rails · PostgreSQL · Hotwire
Services
Rails business app · e-commerce · SEO
Discipline
Tests on what makes money
Rails maintenance services
Le Baroudeur du Vin online wine shop, whose internal tool runs on Rails
The storefront. Every order flows through the Rails OS.
  • InvoicingInvoices generated from the application, straight from orders.
  • InventoryBottle stock tracked in the OS, in step with online sales.
  • LogisticsShipping steps triggered automatically.
  • Product catalogWine listings managed in one place, feeding the shop.

Frequently asked questions

Your questions about Rails upgrades and takeovers

How much do Rails upgrade services cost?

They are quote-based. The price depends on the version gap, the size of the codebase, the number of gems to replace and the existing test coverage. The takeover audit lets us price each step separately, so you stay in control of the budget.

Can you take over a legacy Rails app written by another developer?

Yes, that is the core of this service. We start with a takeover audit of the code, the Rails, Ruby and gem versions, the database and the hosting. You then know exactly what state the application is in and what needs doing first.

My app runs on Rails 4 or 5. Can we jump straight to Rails 8?

No, and that is deliberate. We upgrade one version at a time, for example 5.2, then 6.0, 6.1, 7.0 and so on up to Rails 8. Each step goes to production before the next one starts. It is safer, and every step already brings security fixes.

What if my application has no tests at all?

That is common. Before any upgrade, we write RSpec tests covering the critical flows of your business, such as sign-in, orders, invoicing and exports. They act as a safety net during the upgrade and stay in the project afterwards.

Will my application go down during the migration?

The work is designed to avoid it. It happens on a separate branch with dual boot, so the app runs on both the current version and the next one, and releases are small and reversible. We plan each release with you.

Do we have to move to Hotwire or Kamal?

No. The priority is an application that is up to date and secure. Hotwire, Solid Queue or Kamal are only suggested when they genuinely simplify your app or cut your hosting costs. If you are unsure where to start, a Rails code audit sets out the options.

Our other Rails services

More ways we can help with Rails

Every service below is run by the same team. For the full picture, see our Ruby on Rails agency page.

Rails MVP development

Accounts, Stripe subscriptions, an admin back office and your core feature, live in a few weeks.

€8,000 to €20,000

Rails code audit

Code, security, performance, tests and infrastructure reviewed, with a written report and prioritised fixes.

Custom quote

Rails maintenance services

Security patches, updates, monitoring and small improvements for your app in production.

Custom quote

Your Rails app has no developer left?

Send us your Rails version, your Ruby version and what the application does. We reply within 48 hours with a first assessment and the next steps.

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