---
canonical: 'https://htmlcsstoimage.com/features/url-to-png/ruby-client'
title: 'Screenshot Webpages as PNG in Ruby with the HCTI Gem | HTML/CSS to Image'
description: 'Take webpage screenshots as PNG in Ruby with the htmlcsstoimage-api Gem. Capture a URL with viewport, full-page, selector, and browser controls.'
---

# Take PNG webpage screenshots in Ruby with the HCTI Gem without managing Chrome

Capture public webpages from Ruby with the htmlcsstoimage-api Gem without installing Chrome, running Ferrum or Selenium, or maintaining screenshot storage and delivery.

## Why use the API instead of native Ruby screenshot automation?

- Keep Rails applications and background jobs free of separate browser processes and browser-specific deployment dependencies.
- Set viewport, full-page, selector, timing, color scheme, and browser-state controls as request parameters instead of browser scripts.
- Receive a hosted .png URL without building a separate pipeline for temporary files, uploads, storage, and delivery.

## Complete Ruby request (htmlcsstoimage-api Gem)

Use this request to capture the example webpage as PNG.

```ruby
# gem install htmlcsstoimage-api
require "htmlcsstoimage"

# Uses HCTI_USER_ID and HCTI_API_KEY from the environment.
client = HTMLCSSToImage.new

result = client.url_to_image(
    "https://example.com",
    viewport_height: 630,
    viewport_width: 1200,
)

puts result.url

```

## When to use PNG

PNG preserves sharp text, interface details, and transparency, making it a reliable format for webpage archives and UI captures.

- **Lossless page detail**: Keep text, icons, charts, and interface elements crisp without compression artifacts.
- **Transparent backgrounds**: Preserve transparent page backgrounds when the captured design is intended for overlays or compositing.
- **Reliable visual fidelity**: Use PNG when exact colors and sharp edges matter more than the smallest possible file.

## API request

Send an authenticated `POST` request to `https://hcti.io/v1/image`. Include `url`, `format`, and any viewport, selector, timing, or browser options required for the capture.

```json
{
  "url": "https://example.com",
  "format": "png",
  "viewport_width": 1200,
  "viewport_height": 630
}
```

## Request workflow

1. **Send the webpage URL** — Submit a public URL with format set to png and any viewport, selector, or browser settings.
2. **Chromium loads the page** — The API runs the webpage, styles, fonts, images, and JavaScript in a managed browser environment.
3. **Use the .png URL** — Embed the hosted result, download the file, or save it in your own storage and application records.

## Capture controls and output handling

- Authenticate from trusted server-side code. Do not expose an API key in browser JavaScript, logs, or agent-visible output.
- Use `full_screen`, `selector`, viewport dimensions, timing, and browser options to capture the required page state.
- Treat the returned URL as the generated `png` resource. Download it, embed it, or copy it to configured storage as required.

## Use through MCP

An MCP-compatible agent can connect to `https://mcp.hcti.io` with OAuth and use the connected HTML/CSS to Image account instead of handling an API key directly.

Ask the MCP tool to capture the supplied URL as PNG, or specify `format: png` explicitly in the request.

- [Read the MCP integration documentation](https://docs.htmlcsstoimage.com/integrations/mcp/)

## Related conversions

- [HTML to PNG](https://htmlcsstoimage.com/features/html-to-png/ruby-client.md): Render supplied HTML and CSS as PNG instead of capturing a public webpage.
- [URL to JPEG](https://htmlcsstoimage.com/features/url-to-jpeg/ruby-client.md): JPEG is a practical choice for photographic and content-heavy webpages where broad compatibility and smaller files matter.
- [URL to WebP](https://htmlcsstoimage.com/features/url-to-webp/ruby-client.md): WebP combines modern compression with strong visual quality, making it a good fit for webpage screenshots delivered on the web.
- [URL to PDF](https://htmlcsstoimage.com/features/url-to-pdf.md): Generate paginated documents from public webpages with page sizing, margins, backgrounds, and print styles.

## Reference links

- [URL screenshot API documentation](https://docs.htmlcsstoimage.com/getting-started/url-to-image/)
- [MCP integration documentation](https://docs.htmlcsstoimage.com/integrations/mcp/)
- [Interactive URL to PNG page](https://htmlcsstoimage.com/features/url-to-png/ruby-client)
- [Plans and current limits](https://htmlcsstoimage.com/pricing.md)