# react-helmet-async
[](https://github.com/staylor/react-helmet-async/actions/workflows/ci.yml)
[Announcement post on Times Open blog](https://open.nytimes.com/the-future-of-meta-tag-management-for-modern-react-development-ec26a7dc9183)
This package is a fork of [React Helmet](https://github.com/nfl/react-helmet).
`` usage is synonymous, but server and client now requires `` to encapsulate state per request.
`react-helmet` relies on `react-side-effect`, which is not thread-safe. If you are doing anything asynchronous on the server, you need Helmet to encapsulate data on a per-request basis, this package does just that.
## React 19
React 19 has built-in support for hoisting ``, `<meta>`, `<link>`, `<style>`, and `<script>` elements to `<head>`. Starting with version 3.0.0, this package detects the React version at runtime:
- **React 19+**: `<Helmet>` renders actual DOM elements and lets React handle hoisting them to `<head>`. `<HelmetProvider>` becomes a transparent passthrough. The existing API is fully compatible — you do not need to change any code.
- **React 16–18**: The existing behavior is preserved. `<Helmet>` collects all instances, deduplicates tags, and applies changes to the DOM via manual manipulation (client) or serializes them for the response (server).
> **Note:** `htmlAttributes` and `bodyAttributes` do not have a React 19 equivalent, so they are still applied via direct DOM manipulation on both code paths.
If you are starting a new React 19 project and do not need `htmlAttributes`/`bodyAttributes`, SSR `context` serialization, `onChangeClientState`, `prioritizeSeoTags`, or `titleTemplate` support, you may not need this package at all — React 19's built-in metadata handling may be sufficient.
## Usage
**New in 1.0.0:** No more default export! `import { Helmet } from 'react-helmet-async'`
The main way that this package differs from `react-helmet` is that it requires using a Provider to encapsulate Helmet state for your React tree. If you use libraries like Redux or Apollo, you are already familiar with this paradigm:
```javascript
import React from 'react';
import { createRoot } from 'react-dom/client';
import { Helmet, HelmetProvider } from 'react-helmet-async';
const app = (
<HelmetProvider>
<App>
<Helmet>
<title>Hello World
Hello World
);
createRoot(document.getElementById('app')).render(app);
```
On the server, we will no longer use static methods to extract state. `react-side-effect`
exposed a `.rewind()` method, which Helmet used when calling `Helmet.renderStatic()`. Instead, we are going
to pass a `context` prop to `HelmetProvider`, which will hold our state specific to each request.
```javascript
import React from 'react';
import { renderToString } from 'react-dom/server';
import { Helmet, HelmetProvider } from 'react-helmet-async';
const helmetContext = {};
const app = (
Hello World
Hello World
);
const html = renderToString(app);
const { helmet } = helmetContext;
// helmet.title.toString() etc…
```
> **React 19 SSR note:** When using React 19, ``, `<meta>`, and `<link>` tags rendered inside `<Helmet>` are included directly in the React render output and hoisted to `<head>` by React itself. The `context` object will not be populated with helmet state on React 19. If you rely on the `context` for server rendering, you can render these tags directly in your component tree instead and let React 19 handle them natively.
## Streams
This package only works with streaming if your `<head>` data is output outside of `renderToNodeStream()`.
This is possible if your data hydration method already parses your React tree. Example:
```javascript
import through from 'through';
import { renderToNodeStream } from 'react-dom/server';
import { getDataFromTree } from 'react-apollo';
import { Helmet, HelmetProvider } from 'react-helmet-async';
import template from 'server/template';
const helmetContext = {};
const app = (
<HelmetProvider context={helmetContext}>
<App>
<Helmet>
<title>Hello World
Hello World
);
await getDataFromTree(app);
const [header, footer] = template({
helmet: helmetContext.helmet,
});
res.status(200);
res.write(header);
renderToNodeStream(app)
.pipe(
through(
function write(data) {
this.queue(data);
},
function end() {
this.queue(footer);
this.queue(null);
}
)
)
.pipe(res);
```
> **React 19:** React 19's `renderToReadableStream` natively handles ``, `<meta>`, and `<link>` hoisting during streaming, so the manual context extraction shown above is not necessary.
## Usage in Jest
While testing in using jest, if there is a need to emulate SSR, the following string is required to have the test behave the way they are expected to.
```javascript
import { HelmetProvider } from 'react-helmet-async';
HelmetProvider.canUseDOM = false;
```
> This is only relevant for React 16–18. On React 19, `HelmetProvider` is a passthrough and `canUseDOM` has no effect.
## Prioritizing tags for SEO
It is understood that in some cases for SEO, certain tags should appear earlier in the HEAD. Using the `prioritizeSeoTags` flag on any `<Helmet>` component allows the server render of react-helmet-async to expose a method for prioritizing relevant SEO tags.
In the component:
```javascript
<Helmet prioritizeSeoTags>
<title>A fancy webpage
```
In your server template:
```javascript
${helmet.title.toString()}
${helmet.priority.toString()}
${helmet.meta.toString()}
${helmet.link.toString()}
${helmet.script.toString()}
...
```
Will result in:
```html
A fancy webpage
...
```
A list of prioritized tags and attributes can be found in [constants.ts](./src/constants.ts).
> **React 19:** The `prioritizeSeoTags` flag has no effect on React 19, since tags are rendered as regular JSX elements and their order in `` is determined by React's rendering order.
## Usage without Context
You can optionally use `` outside a context by manually creating a stateful `HelmetData` instance, and passing that stateful object to each `` instance:
```js
import React from 'react';
import { renderToString } from 'react-dom/server';
import { Helmet, HelmetData } from 'react-helmet-async';
const helmetData = new HelmetData({});
const app = (
Hello World