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Width & Height Parameters

The width and height parameters control the viewport dimensions for capturing images.

Specifications

Width Parameter

Property	Value
Type	integer
Required	No
Default	1440
Range	1-5000
API	Both HTML/CSS and Screenshot APIs

Height Parameter

Property	Value
Type	integer
Required	No
Default	900
Range	1-5000
API	Both HTML/CSS and Screenshot APIs

Description

These parameters determine:

The viewport size for rendering content
The dimensions of the output image (unless fullpage is true)
The responsive breakpoint for the content

When using DPI values greater than 1, the actual rendered dimensions will be multiplied by the DPI value. For example:

With width=1920 and DPI=2, the final image will be 3840px wide
With height=1080 and DPI=2, the final image will be 2160px tall

To maintain specific output dimensions when using higher DPI:

Either divide your desired dimensions by the DPI value
Or omit width/height to let the image scale naturally with DPI

See the DPI parameter documentation for more details.

Examples

Basic Dimensions

{
    "html": "<div>Responsive Content</div>",
    "width": 1920,
    "height": 1080
}

Mobile Viewport

{
    "url": "https://example.com",
    "width": 375,
    "height": 667
}

Tablet Viewport with Custom Height

{
    "html": "<div>Tablet Content</div>",
    "width": 768,
    "height": 1024,
    "dpi": 2
}

Larger dimensions increase processing time and memory usage. For high-resolution images, consider using a smaller viewport with a higher DPI value instead of very large dimensions.

Common Viewport Sizes

Here are some common viewport sizes you might want to use:

Device	Width	Height
Desktop HD	1920	1080
Desktop	1440	900
Laptop	1366	768
Tablet	768	1024
Mobile	375	667

When using responsive designs, test your content at multiple viewport sizes before locking in a render width.

Common values

1200x630 - Open Graph image, Twitter, LinkedIn share previews.
1080x1080 - Instagram square post.
1280x720 - YouTube thumbnail.
1920x1080 - Desktop screenshot.
375x667 - Mobile screenshot at iPhone SE viewport.
1240x1754 - A4 portrait at 150 DPI, useful for invoices and certificates.

When to use

Set width and height whenever you need a specific output size, especially for social platforms with rigid spec requirements. Leave them at the defaults (1440x900) for general-purpose renders. For full-page captures, set width to the device width and use fullpage to let the height grow.

Common mistakes

Forgetting that DPI multiplies dimensions. A width: 1200 with dpi: 2 produces a 2400px file. Either divide your target by the DPI or omit width and let DPI scale.
Setting unusually large dimensions. A 5000x5000 render eats memory and time. Prefer a smaller viewport with higher DPI when you want a sharp file.

Documentation