What It Really Takes to Migrate from Vue 2 to Vue 3

If you’re thinking about migrating your app from Vue 2 to Vue 3, it’s important to understand what’s actually involved. This isn’t a quick version bump — it’s a major project that touches almost every part of your codebase.

Vue 3 introduced a ton of changes under the hood. The Composition API is probably the flashiest, but it’s not just about new syntax. Vue 3 changes how reactivity works, shifts how you should structure components, updates lifecycle hooks, and removes features that were common in Vue 2 projects. Even if you’re not planning to fully switch to the Composition API, you’re still going to deal with breaking changes.

The thing is, migrating to Vue 3 usually means way more than just updating Vue itself. Most real-world apps rely on a big stack of third-party libraries, tooling, and custom components. If any part of your stack isn't ready for Vue 3, you're stuck either updating, replacing, or rewriting it. In a lot of cases, it's a combination of all three.
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It’s Not Just Vue — It’s Everything

When you plan a Vue 3 migration, you're also signing up for updates to things like Vue Router, Vuex (or switching to Pinia), and libraries like Vuetify or BootstrapVue. And some of those projects didn’t make it to Vue 3 at all. BootstrapVue, for example, never released a Vue 3 version. So if you're using it, you're looking at either:

• Rebuilding UI components from scratch
• Finding a different library
• Or some messy mix of both

And even if your libraries have Vue 3 versions, that doesn’t mean they’re drop-in upgrades. The APIs often change, and you'll need to refactor your code to match.

On top of that, your tooling probably needs updates too. Webpack, Babel, ESLint configs, TypeScript versions — they all have to work with Vue 3. Sometimes upgrading those breaks other parts of your app. It’s a big, interconnected puzzle.
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How Much Work Are We Talking About?

Most teams underestimate how much code they’ll need to touch. The general rule of thumb is that migrating an app like this means:

• Updating at least 75% of your codebase
• Multiplying that estimate by at least 1.3x to account for all the extra testing, dependency fixes, and team ramp-up time

So if you think the direct code changes will take a month, you’re realistically looking at closer to 5-6 weeks once you factor in everything else.

Even if your app is smaller, plan for months — not weeks — to complete the migration, especially if you need to stay live and stable during the process.

Real-world example: when Storyblok migrated their app to Vue 3, it took them around 18 months. That included migrating about 180 components, updating internal libraries, and training their team to use the new Vue 3 patterns. And Storyblok’s devs knew Vue inside and out.
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What Else Should You Plan For?

Training your team: Even experienced Vue 2 developers will need time to get comfortable with Vue 3's changes. It's not just new syntax — it's a new way of thinking about state, lifecycles, and reactivity.

Refactoring patterns: Vue 3's Composition API encourages better separation of concerns and more flexible architecture. You'll probably want to refactor some of your old Vue 2 patterns while you're touching the code.

Testing everything: Migrating means bugs. Even careful migrations usually break small edge cases. You'll need a solid QA plan and time to thoroughly test everything.

Performance tuning: Vue 3 offers better performance out of the box thanks to internal optimizations like the Proxy-based reactivity system and better dependency tracking. But to fully take advantage of the improvements, some parts of your app might need targeted refactoring.
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Where HeroDevs Comes In

‍If your team isn’t ready to migrate to Vue 3 yet, HeroDevs offers Vue 2 Never-Ending Support (NES). We provide secure, drop-in replacements that keep your Vue 2 app compliant, patched, and production-safe—without forcing you into an upgrade before you’re ready. You get time to plan your migration on your terms, while we handle the security and stability you need to stay online with confidence.
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Bottom Line

Migrating from Vue 2 to Vue 3 is doable — and Vue 3 is a big step forward once you're there — but it’s not a simple upgrade. It’s a serious project that needs planning, budget, and time.

If your app is large or complex, it’s worth asking whether you have the bandwidth for a full migration right now. Sometimes, it might make more sense to stabilize your Vue 2 app first, then migrate when you can give it the focus it needs.

Either way, go in with your eyes open. It's better to be realistic about the work involved than to find yourself halfway through and stuck.

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