Image output

PNG with transparent background

Generate images with a transparent backgound

You can create PNGs with a transparent background by simply adding body { background: transparent } to your CSS. Take a look at this example.

Note: this only works for PNGs. If you render the image as a JPG, the background will show as white.

Interactive example

Edit and render this image

Change the HTML, CSS, or API options. The browser preview updates as you edit; select Image to render the final output through the API.

Content

Adjust how content is rendered by adjusting these settings.

URL ?

Pass a publicly available URL and the API will capture it. (Only applies when a URL is provided)

Google Fonts ?

Google fonts to load. Separate multiple families with a pipe, such as Roboto|Open Sans, and set font-family in the CSS.

Selector ?

A CSS selector for an element in the HTML. We’ll crop the image to this specific element.

Transparent Background ?

Removes the background from the rendered image.

Image size & Viewport

By default images are cropped to the outermost HTML element or the chosen selector. Adjust viewport and sizing settings below.

Full Screen ?

Take a screenshot of the entire screen (Only applies when a URL is provided)

Device Scale ?

Adjusts the screenshot pixel ratio. HTML and template renders default to 2; URL renders default to 1.

Viewport ?

Height

Width

Set the height and width of Chrome's viewport. Setting a viewport disables automatic cropping.

Landscape Viewport

Sets the emulated viewport orientation to landscape.

Mobile Viewport

Makes the emulated viewport behave like a mobile device and honor mobile viewport behavior.

Touch Viewport

Makes the emulated viewport report support for touch events.

Timing

By default the API generates a screenshot once everything is loaded. If the page executes JavaScript, you may want extra time before the image is rendered.

Ms Delay ?

Adds extra time for JavaScript to execute before the screenshot is taken. Start with 500 milliseconds if the page renders blank.

Max Wait Ms ?

Sets a limit on how long to wait before taking the screenshot when irrelevant content continues loading.

Render When Ready ?

Waits for the page to signal that the screenshot is ready instead of capturing after normal loading.

Browser Context

These settings impact how Chrome is started, giving you more control when taking screenshots.

Color Scheme ?

Set Chrome to render as if the user prefers light or dark mode.

Media Type

Set Chrome to render the page using print or screen media styles.

Timezone ?

Render the page with Chrome set to a specified timezone.

Block Consent Banners ?

Attempt to block cookie/consent banners from displaying. (Only applies when a URL is provided)

Identify as HCTI

Send X-HCTI-SCREENSHOT: 1 with the top-level page navigation. (Only applies when a URL is provided)

Example code

Use this request in your app

Choose a language and copy a complete request using this example's HTML, CSS, and API options.

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io"
    "net/http"
    "os"
    "time"
)

func main() {
    request := map[string]any{
        "html": `
                <div class="wrapper">
                  <svg id="sw-js-blob-svg" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" version="1.1">
                    <defs>
                      <linearGradient id="sw-gradient" x1="0" x2="1" y1="1" y2="0">
                        <stop id="stop1" stop-color="rgba(248, 117, 55, 1)" offset="0%"></stop>
                        <stop id="stop2" stop-color="rgba(251, 168, 31, 1)" offset="100%"></stop>
                      </linearGradient>
                    </defs>
                    <path fill="url(#sw-gradient)" d="M24.6,-27.9C31.2,-23.7,35.5,-15.4,34.6,-7.9C33.8,-0.5,27.8,6.1,23.1,12.4C18.3,18.7,14.8,24.8,9.5,27.3C4.2,29.8,-2.9,28.6,-10.8,26.9C-18.7,25.2,-27.3,23,-33.1,17.1C-38.9,11.2,-41.8,1.7,-38.9,-5.5C-36,-12.7,-27.5,-17.6,-20,-21.7C-12.6,-25.7,-6.3,-29,1.3,-30.6C9,-32.2,17.9,-32.1,24.6,-27.9Z" width="100%" height="100%" transform="translate(50 50)" stroke-width="0" style="transition: all 0.3s ease 0s;"></path>
                  </svg>
                </div>
                `,
        "css": `
               .wrapper {
                 width: 400px;
                 height: 400px;
               }
               body {
                 background: transparent;
               }
               
               `,
        "render_when_ready": false,
        "transparent_background": true,
    }

    body, err := json.Marshal(request)
    if err != nil {
        panic(err)
    }
    httpRequest, err := http.NewRequest(http.MethodPost, "https://hcti.io/v1/image", bytes.NewReader(body))
    if err != nil {
        panic(err)
    }
    httpRequest.SetBasicAuth(os.Getenv("HCTI_API_ID"), os.Getenv("HCTI_API_KEY"))
    httpRequest.Header.Set("Content-Type", "application/json")

    client := &http.Client{Timeout: 30 * time.Second}
    response, err := client.Do(httpRequest)
    if err != nil {
        panic(err)
    }
    defer response.Body.Close()
    responseBody, err := io.ReadAll(response.Body)
    if err != nil {
        panic(err)
    }
    if response.StatusCode >= http.StatusBadRequest {
        panic(fmt.Sprintf("HCTI request failed (%d): %s", response.StatusCode, responseBody))
    }

    var result struct {
        URL string `json:"url"`
    }
    if err := json.Unmarshal(responseBody, &result); err != nil {
        panic(err)
    }
    fmt.Println(result.URL)
}

Read the Go Docs

Request configuration

Options used in this example

These values are sent with the HTML and CSS to control how HCTI loads the page and captures the final screenshot. You can change each one in the editor above.

Transparent Background

transparent_background

True

Specifies whether the image is rendered with a transparent background.

Learn about this option

From code to screenshot

How HCTI examples work

HTML/CSS to Image renders HTML and CSS in hosted Chrome, then captures the result as an image or PDF. Each example combines real source code with the API options used for the render, so it is both a working demo and a starting point for your own request.

Edit the source and options above to test changes in the browser, then render through the API to see the production result.

Common questions

Can I use the HTML and CSS from these examples?

Yes. Open an example to inspect and edit its complete HTML, CSS, and render options. Use it as a starting point, then send the resulting request from your application.

What is the difference between an example and a template?

Examples are complete API requests built from HTML and CSS. Templates are saved, reusable designs created in the visual editor and rendered repeatedly with different variable values.

Does HCTI create screenshots and PDFs?

Yes. HCTI can render HTML and CSS or capture a public webpage as an image, and it can generate PDFs when you need document output instead of a screenshot.