Vue 2 vs Vue 3 in 2026: Understanding the Differences for Fintech

Vue.js 2 has been powering interactive web development for quite a few years. The progressive JavaScript framework is one of the most preferred technologies for developing web interfaces.

However, if you are stuck using Vue 2, your work may soon become outdated and open to security risks, especially in fintech, where security vulnerabilities in your frontend can expose sensitive financial data and bring regulatory scrutiny.

Vue 3 was released in September 2020 and has since become the current, recommended version.

While we still see a lot of projects using Vue 2, especially in legacy environments, it’s important to start switching over to ensure you are working with a framework that receives consistent updates and support.

Let’s take a look at everything you need to know about the differences between the two frameworks and which one you should choose for your Vue development project. 

If you need a skilled Vue developer for your fintech project, we can assist.

At Trio, we pre-vet developers with several years of production experience in financial applications. They just need to be picked based on your specific requirements, cutting placement and onboarding to as little as 3-5 days.

View capabilities.

What Is Vue.js 2?

Vue 2 came out in October 2016, exactly four years before Vue 3, and quickly earned a reputation as a lightweight, simple, and versatile development framework.

At Trio, our developers used it to create responsive and progressive web interfaces that integrated well with other technologies.

However, Vue 2 saw use by companies all over the world. This can be attributed to both its multiple benefits and the gradual migration timeline the ecosystem needed.

Vue 2 reached end-of-life in December 2023, meaning it no longer receives security patches, bug fixes, or new features, and any Vue 2 project still in production today carries an accumulating security risk.

When To Use Vue 2, and When Not To

Vue 2 should still be the working context if:

• Your application relies on dependencies not yet compatible with Vue 3 (this will be rare, as most major libraries have long since migrated)
• Your work involves maintaining existing Vue 2 code in a codebase where migration risk outweighs benefit in the short term.

In every other scenario, migrating from Vue 2 to Vue 3 is the right call, since Vue 2 now sits in maintenance mode with no active development path.

We never recommend this as the way to go in fintech. If you are currently running Vue 2, migration is critical.

Running an unpatched frontend framework in a regulated environment creates massive issues during security and compliance reviews.

What Is Vue.js 3?

Vue 3 was announced as a smaller, faster, and more maintainable alternative to Vue 2.

With the more modern version of the framework. It came with the addition of newer features and also addressed several drawbacks of Vue 2.

In older versions of Vue, the code tended to become complex and less readable as it grew.

Vue 3 attempts to solve this and other issues while preserving similar syntax conventions, making the switch more approachable than it might first appear.

When To Use Vue 3, and When Not To

If you or your team starts work on a new Vue development project, Vue 3 should be your default.

It offers superior performance over Vue 2, as we have already mentioned, and is also easier to understand at scale.

For financial products, you need to be prepared to scale in both volume and complexity over time. Vue 3 will give you the foundation to prevent bugs long-term and make it a lot easier for your developers to maintain and adapt long-term.

A Detailed Look at Why Vue 3 Matters for Fintech Applications

We have already explained the basics of why Vue 3 should always be used in Fintech opportunities. You’ll get better performance, improved TypeScript support, a more predictable reactivity system, and active maintenance.

But, there are many reasons beyond basic web development considerations that make Vue 3 critical for fintech specifically:

• Security and the end-of-life risk: Vue 2 no longer receives security patches, which creates compliance exposure depending on your regulatory environment. PCI-DSS, GDPR, and others require that software components receive timely security updates.
• TypeScript and reduced runtime errors in financial logic: Calculations, currency handling, date arithmetic, and state management are sensitive to type errors. Vue 3's native TypeScript support helps catch these errors at compile time.
• Complex reactive state: Fintech dashboards often manage layered, nested state. Vue 3's Proxy-based reactivity system handles this predictably and automatically.
• Performance on mobile: Many fintech users access financial products on outdated mobile hardware with variable network connectivity. Vue 3's smaller bundle size (roughly 22KB gzipped vs 33KB) and improved rendering performance load faster and work better in these conditions.
• Codebase maintainability at scale: As fintech products get more complex, the Composition API's feature-based code organisation makes it considerably easier to understand what a component does, audit its behaviour, and make changes.

The Reactivity System: Object.defineProperty vs Proxy

The reactivity system is by far the most significant difference between Vue 2 and Vue 3, and the one that causes the most production issues in Vue 2 codebases at scale.

Vue 2's reactivity system uses Object.defineProperty to track changes to data properties.

The limitation here is that Object.defineProperty cannot detect property additions or deletions on an object after it's been made reactive, and it can’t track changes to array indices directly either.

This led to the well-known Vue.set() workarounds and array mutation method wrappers that ended up confusing developers and creating subtle bugs in large applications.

Vue 3's reactivity system replaces Object.defineProperty with JavaScript Proxy.

A Proxy wraps the entire object and intercepts all operations (including property additions, deletions, and array index changes) without the caveats.

The result is a more predictable reactive state that behaves consistently across all data types and object shapes.

In practice, this means:

• Adding a new property to a reactive object in Vue 3 triggers reactivity automatically. No Vue.set() needed
• Deleting a property from a reactive object works reactively out of the box
• Array changes by index (arr[0] = newVal) now trigger reactive updates, which Vue 2 simply couldn't handle.

For fintech applications managing complex, nested states that include transaction objects, account hierarchies, and real-time data feeds, this is a massive improvement.

The Differences Between Vue 2 and Vue 3: Other Key Changes

While the reactivity system is probably the biggest change, there are a bunch of other factors that you need to take into account as well.

The Composition API vs the Options API

Another big change introduced in Vue 3 is the Composition API.

The Options API in Vue 2 requires the separation of code into different properties like data, methods, computed, and watch, which means related logic gets scattered across sections as components grow.

The Composition API of Vue 3 lets your developers group code by feature, instead of type.

That is beneficial because it means that all the logic for a single feature, around things like its reactive state, its computed properties, its methods, and its lifecycle hooks, sits together in one place, inside a setup() function.

What is great here is that Vue 3 supports both APIs, so teams migrating from Vue 2 can continue using the Options API without changes.

The Composition API becomes most useful as component complexity grows, or when logic needs to be shared (reused) across multiple components through composables, which Vue 2 previously handled via mixins.

This is critical in fintech dashboards specifically, where multiple components might share logic for currency formatting, date handling, or transaction status resolution.

TypeScript Support

Vue 2 had TypeScript integration available, but it required third-party decorators and significant configuration to work well.

Type checking on props, events, and component internals remained awkward compared to TypeScript-native frameworks.

Vue 3, on the other hand, was rewritten in TypeScript from the ground up.

The improved TypeScript support means better type inference for the Composition API, typed props and emits, and TypeScript integration that works well without decorators or extra configuration.

For fintech teams where type safety reduces runtime errors in financial logic, this improved TypeScript integration is a massive engineering improvement, especially in enterprise environments.

Performance Improvements and the Virtual DOM Rewrite

Vue 3's virtual DOM was rewritten with a new compiler strategy that produces better performance on component rendering.

Several specific optimisations distinguishing Vue 3 include:

• Static node hoisting: The Vue 3 compiler identifies static nodes in a template and hoists them outside the render function. They get created once and reused, rather than recreated on every render cycle.
• Patch flag hints: The compiler marks dynamic nodes with patch flags that tell the runtime exactly what type of change to expect, so the DOM update can skip unnecessary comparisons
• Tree-shaking: Vue 3 is tree-shakable at the module level. Built-in components and APIs that a project doesn't use don't end up in the production bundle.
• Smaller bundle sizes: Vue 3 is roughly 22KB gzipped, down from Vue 2's roughly 33KB. That 55% reduction in size matters for performance on lower-end devices and slower network conditions.

While each of these seems like it would provide very little benefit, everything adds up.

Benchmarks from the Vue core team show Vue 3 rendering up to 55% faster than Vue 2.

Multiple Root Elements and Fragments

Vue 2 allows only a single root node in the template, which means that every component needs a wrapping <div> or similar unnecessary wrapper element.

Vue 3 removes this restriction through fragments.

Components can have multiple root elements in the same template, which ultimately produces cleaner HTML output and eliminates wrapper elements that existed only to work around the Vue 2 limitation.

When you optimize your fintech with grid structures and include security measures such as accessibility requirements, removing those unnecessary wrapper elements can simplify both styling and screen reader behaviour.

Lifecycle Hooks

In Vue 2, lifecycle hooks are accessed directly from the component options.

We have already discussed how, in Vue 3, lifecycle hooks live inside the setup() method. They need to be imported explicitly, and follow a naming convention with an on prefix:

• beforeCreate and created become unnecessary in Vue 3 since their logic goes directly in setup()
• mounted becomes onMounted
• updated becomes onUpdated
• unmounted becomes onUnmounted (previously destroyed in Vue 2)

This change pairs well with the Composition API's feature-based organisation.

Computed Properties

Using computed properties in Vue 2 involves adding a computed field to the options object.

In Vue 3, developers need to import computed into the component before using it inside setup().

// Vue 3

import { computed, ref } from 'vue'

setup() {

  const count = ref(0)

  const doubled = computed(() => count.value * 2)

  return { count, doubled }

}

This might seem like additional work, but it prevents importing unnecessary packages that were never used.

Emitting Events

In Vue 2, this.$emit sends an event to a parent component directly.

Vue 3 gives more control over how properties and methods are accessed through the emit function, which is accessed via the context object in setup():

// Vue 3

setup(props, context) {

  context.emit('my-event', payload)

}

Vue 3 also introduces the emits option, which allows components to declare the events they emit explicitly.

This has the added benefit of improving both TypeScript type checking and developer tooling support.

Teleport

The portal feature means that you can now render part of a component into a different location in the DOM tree.

To do this, Vue 2 required a third-party plugin called portal-vue, but Vue 3 now includes this as a built-in feature through the <teleport> tag.

Modals, tooltips, and notifications, which are all common in fintech dashboards, are typical use cases where Teleport prevents z-index and overflow issues that arise when a modal renders inside a deeply nested component.

Transaction confirmation dialogs, fraud alert overlays, and two-factor authentication prompts are also good examples.

State Management: Vuex to Pinia

Vue 2 used Vuex for state management. Vue 3 supports both Vuex 4 (for Vue 2 to Vue 3 migrations that want to preserve the existing state management layer) and Pinia, which is now the official recommended state management library for Vue 3 new projects.

Pinia offers a simpler API with no mutations, better TypeScript integration, and composable store definitions that align naturally with the Composition API.

This is all critical in financial applications where you will be managing global state around user accounts, session data, and real-time balance updates, where you will need to avoid Vuex's mutation-heavy pattern.

Vue 3 Migration Guide: What Breaking Changes to Expect

Migrating from an existing Vue 2 project to Vue 3 is essential, but it can open you up to certain risks.

The official Vue 3 migration guide at v3-migration.vuejs.org documents every breaking change, so make sure to check it out in depth.

However, there are several that warrant specific attention:

• Vue.set() and Vue.delete() are removed, so any Vue 2 code using them needs to be updated
• $listeners is removed and merged into $attrs in Vue 3
• $children is removed, and $refs or dependency injection replace this pattern
• Filters are replaced with computed properties or methods
• v-model changes default prop and event names change on custom components
• keyCode modifiers are removed, so you need to use named key modifiers instead
• Object.define property-based reactivity caveats disappear.

The @vue/compat compatibility build lets teams run Vue 3 in Vue 2 compatibility mode during migration, with runtime warnings for deprecated APIs.

This allows a phased migration approach rather than a full rewrite, which gives you the time to ensure each component works correctly before moving on to the next, but it does add bundle weight and should definitely not be used as a long-term solution.

We always recommend this route in fintech. The alternative, known as a big-bang migration, carries large quantities of risk.

TypeScript with Vue 3: A Practical Improvement

Vue 3's TypeScript integration is a particularly noteworthy change, because it affects code organisation, tooling, and long-term maintainability in ways that Vue 2's optional TypeScript support doesn't.

Using TypeScript with Vue 3 through the <script setup> syntax and defineProps/defineEmits macros produces better type inference automatically:

// Vue 3 with TypeScript

<script setup lang="ts">

const props = defineProps<{

  amount: number

  currency: string

}>()

const emit = defineEmits<{

  (e: 'update', value: number): void

}>()

</script>

This is a massive upgrade when you consider how, in Vue 2 with TypeScript, you needed class-based components or vue-class-component decorators, adding considerably more boilerplate to get the same result.

The example we provided above is also a realistic component signature. Props like Amount and currency benefit from the strict typing, since this approach allows you to reduce errors in financial calculations.

Related Reading: Vue vs React: Is Vue Up Next?

Conclusion

Both Vue 2 and Vue 3 represent excellent web development frameworks with strong community support.

But Vue is incredibly outdated at this point, and using it in your production applications is going to create security vulnerabilities that most fintechs can’t afford. 

Vue 3's improvements, like its Proxy-based reactivity system, the Composition API, improved TypeScript support, smaller bundle sizes, and the virtual DOM rewrite, also add up to a meaningfully different development experience.

For hiring Vue.js developers who understand both versions and the migration path between them, and who understand what it takes to create applications in heavily regulated environments, request a consult.