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fix(render): strip React 19 auto-injected image preload links #3109

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53759c5
fix(render): strip React 19 auto-injected image preload links from em…
yuribodo Mar 25, 2026
0da43ff
fix(img): use fetchPriority="low" to prevent React 19 preload injection
yuribodo Mar 29, 2026
cf0897e
fix: update remaining snapshots with fetchpriority="low" attribute
yuribodo Mar 29, 2026
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2 changes: 1 addition & 1 deletion packages/img/src/img.spec.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ describe('<Img> component', () => {
<Img alt="Cat" height="300" src="cat.jpg" width="300" />,
);
expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="cat.jpg"/><!--$--><img alt="Cat" height="300" src="cat.jpg" style="display:block;outline:none;border:none;text-decoration:none" width="300"/><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><img alt="Cat" fetchPriority="low" height="300" src="cat.jpg" style="display:block;outline:none;border:none;text-decoration:none" width="300"/><!--/$-->"`,
);
});
});
4 changes: 4 additions & 0 deletions packages/img/src/img.tsx
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Expand Up @@ -7,6 +7,10 @@ export const Img = React.forwardRef<HTMLImageElement, ImgProps>(
<img
{...props}
alt={alt}
// Setting fetchPriority to "low" prevents React 19's SSR from
// auto-injecting <link rel="preload"> tags for every image, which are
// unnecessary noise in email HTML. Email clients ignore this attribute.
fetchPriority="low"
height={height}
ref={ref}
src={src}
Expand Down
8 changes: 4 additions & 4 deletions packages/preview-server/src/utils/get-email-component.spec.ts
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Expand Up @@ -28,10 +28,6 @@ describe('getEmailComponent()', () => {
"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html dir="ltr" lang="en">
<head>
<link rel="preload" as="image" href="/static/vercel-logo.png" />
<link rel="preload" as="image" href="/static/vercel-user.png" />
<link rel="preload" as="image" href="/static/vercel-arrow.png" />
<link rel="preload" as="image" href="/static/vercel-team.png" />
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" />
<meta name="x-apple-disable-message-reformatting" />
<!--$-->
Expand Down Expand Up @@ -81,6 +77,7 @@ describe('getEmailComponent()', () => {
<td>
<img
alt="Vercel Logo"
fetchpriority="low"
height="37"
src="/static/vercel-logo.png"
style="display:block;outline:none;border:none;text-decoration:none;margin-right:auto;margin-left:auto;margin-bottom:0;margin-top:0"
Expand Down Expand Up @@ -132,6 +129,7 @@ describe('getEmailComponent()', () => {
data-id="__react-email-column">
<img
alt="alanturing&#x27;s profile picture"
fetchpriority="low"
height="64"
src="/static/vercel-user.png"
style="display:block;outline:none;border:none;text-decoration:none;border-radius:9999px"
Expand All @@ -142,6 +140,7 @@ describe('getEmailComponent()', () => {
data-id="__react-email-column">
<img
alt="Arrow indicating invitation"
fetchpriority="low"
height="9"
src="/static/vercel-arrow.png"
style="display:block;outline:none;border:none;text-decoration:none"
Expand All @@ -152,6 +151,7 @@ describe('getEmailComponent()', () => {
data-id="__react-email-column">
<img
alt="Enigma team logo"
fetchpriority="low"
height="64"
src="/static/vercel-team.png"
style="display:block;outline:none;border:none;text-decoration:none;border-radius:9999px"
Expand Down
6 changes: 4 additions & 2 deletions packages/react-email/src/commands/testing/export.spec.ts
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Expand Up @@ -20,8 +20,6 @@ test('email export', { retry: 3 }, async () => {
"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html dir="ltr" lang="en">
<head>
<link rel="preload" as="image" href="/static/vercel-logo.png" />
<link rel="preload" as="image" href="/static/vercel-arrow.png" />
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" />
<meta name="x-apple-disable-message-reformatting" />
<!--$-->
Expand Down Expand Up @@ -71,6 +69,7 @@ test('email export', { retry: 3 }, async () => {
<td>
<img
alt="Vercel Logo"
fetchpriority="low"
height="37"
src="/static/vercel-logo.png"
style="display:block;outline:none;border:none;text-decoration:none;margin-right:auto;margin-left:auto;margin-bottom:0;margin-top:0"
Expand Down Expand Up @@ -121,6 +120,7 @@ test('email export', { retry: 3 }, async () => {
data-id="__react-email-column">
<img
alt="undefined&#x27;s profile picture"
fetchpriority="low"
height="64"
style="display:block;outline:none;border:none;text-decoration:none;border-radius:9999px"
width="64" />
Expand All @@ -130,6 +130,7 @@ test('email export', { retry: 3 }, async () => {
data-id="__react-email-column">
<img
alt="Arrow indicating invitation"
fetchpriority="low"
height="9"
src="/static/vercel-arrow.png"
style="display:block;outline:none;border:none;text-decoration:none"
Expand All @@ -140,6 +141,7 @@ test('email export', { retry: 3 }, async () => {
data-id="__react-email-column">
<img
alt="undefined team logo"
fetchpriority="low"
height="64"
style="display:block;outline:none;border:none;text-decoration:none;border-radius:9999px"
width="64" />
Expand Down
4 changes: 2 additions & 2 deletions packages/render/src/browser/render-web.spec.tsx
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Expand Up @@ -54,7 +54,7 @@ describe('render on the browser environment', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);
});

Expand Down Expand Up @@ -108,7 +108,7 @@ describe('render on the browser environment', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);
});

Expand Down
4 changes: 2 additions & 2 deletions packages/render/src/edge/render.spec.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@ describe('render on the edge', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);
});

Expand Down Expand Up @@ -108,7 +108,7 @@ describe('render on the edge', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);
});

Expand Down
6 changes: 3 additions & 3 deletions packages/render/src/node/render-edge.spec.tsx
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Expand Up @@ -36,7 +36,7 @@ describe('render on the edge', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);

vi.resetAllMocks();
Expand Down Expand Up @@ -92,7 +92,7 @@ describe('render on the edge', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);
});

Expand Down Expand Up @@ -141,7 +141,7 @@ describe('render on the edge', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);
});
});
Expand Down
4 changes: 2 additions & 2 deletions packages/render/src/node/render-node.spec.tsx
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Expand Up @@ -41,7 +41,7 @@ describe('render on node environments', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);

vi.resetAllMocks();
Expand Down Expand Up @@ -125,7 +125,7 @@ describe('render on node environments', () => {
const actualOutput = await render(<Template firstName="Jim" />);

expect(actualOutput).toMatchInlineSnapshot(
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><link rel="preload" as="image" href="img/test.png"/><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
`"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--$--><h1>Welcome, <!-- -->Jim<!-- -->!</h1><img alt="test" fetchPriority="low" src="img/test.png"/><p>Thanks for trying our product. We&#x27;re thrilled to have you on board!</p><!--/$-->"`,
);
});

Expand Down
1 change: 1 addition & 0 deletions packages/render/src/shared/utils/pretty.spec.ts
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Expand Up @@ -9,7 +9,7 @@
'utf8',
);

expect(await pretty(stripeHTML)).toMatchInlineSnapshot(`

Check failure on line 12 in packages/render/src/shared/utils/pretty.spec.ts

View workflow job for this annotation

GitHub Actions / tests

src/shared/utils/pretty.spec.ts > pretty > prettifies Preview component's complex characters correctly 

Error: Snapshot `pretty > prettifies Preview component's complex characters correctly 1` mismatched

- Expected
+ Received

@@ -36,11 +36,10 @@
                <tbody>
                  <tr>
                    <td>
                      <img
                        alt="Stripe"
-                       fetchpriority="low"
                        height="21"
                        src="/static/stripe-logo.png"
                        style="display:block;outline:none;border:none;text-decoration:none"
                        width="49" />
                      <hr

 ❯ src/shared/utils/pretty.spec.ts:12:38
"<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!--$-->
<html dir="ltr" lang="en">
Expand Down Expand Up @@ -50,6 +50,7 @@
<td>
<img
alt="Stripe"
fetchpriority="low"
height="21"
src="/static/stripe-logo.png"
style="display:block;outline:none;border:none;text-decoration:none"
Expand Down
2 changes: 1 addition & 1 deletion packages/render/src/shared/utils/testing/template.tsx
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Expand Up @@ -7,7 +7,7 @@ interface TemplateProps {
export const Template: React.FC<Readonly<TemplateProps>> = ({ firstName }) => (
<>
<h1>Welcome, {firstName}!</h1>
<img alt="test" src="img/test.png" />
<img alt="test" fetchPriority="low" src="img/test.png" />
<p>Thanks for trying our product. We're thrilled to have you on board!</p>
</>
);
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