# Go - HTML to Image Example

Generate PNG, JPG, WebP, and PDF output with Go, using HTML/CSS or reusable templates rendered in Google Chrome.

## Generating images with Go

1.  Send your HTML/CSS to the API.
2.  The API renders it in Google Chrome.
3.  Read the generated image URL from the JSON response.

See [Creating an image](/getting-started/using-the-api/#creating-an-image) for request parameters. A response includes the image's `url` and `id`.

![Example image generated from HTML with Go](/assets/images/dog-rates-example.png)

## Authentication with Go

Use HTTP Basic authentication with your API ID as the username and API key as the password. Find both in the [dashboard](https://htmlcsstoimage.com/dashboard). Keep credentials in server-side configuration or environment variables.

## Go example code

The example sends a POST request to `https://hcti.io/v1/image`. Image creation requires `images:create`. See [authentication and API keys](/getting-started/using-the-api/api-keys/) for scoped credentials and access errors.

## Official Go client

For typed requests, responses, and signed URL helpers, use the official [`github.com/htmlcsstoimage/go-client`](https://pkg.go.dev/github.com/htmlcsstoimage/go-client) module. Requires Go 1.21 or newer.

```bash
go get github.com/htmlcsstoimage/go-client
```

```go
package main


import (
  "context"
  "fmt"
  "log"


  "github.com/htmlcsstoimage/go-client"
)


func main() {
  client := hcti.NewClient("your-api-id", "your-api-key")


  image, err := client.CreateImage(context.Background(), &hcti.HTMLImageRequest{
    HTML:        "<div class='box'>Go ✅</div>",
    CSS:         hcti.Ptr(".box { border: 4px solid #03B875; padding: 20px; font-family: 'Roboto'; }"),
    GoogleFonts: hcti.GoogleFonts{"Roboto"},
  })
  if err != nil {
    log.Fatal(err)
  }
  fmt.Println(image.URL)
}
```

The module’s package name is `hcti`. Alternatively, use `hcti.NewClientFromEnv()` to load `HCTI_API_ID` and `HCTI_API_KEY`; it returns a client and an error. Optional request fields use pointers: `hcti.Ptr(false)`, `hcti.Ptr(0)`, and `hcti.Ptr("")` send explicit values, while nil leaves the field unspecified.

The client also supports URL screenshots, PDF options, templates, batches, image deletion, resizing and cropping, and signed URLs. See the [Go client repository](https://github.com/htmlcsstoimage/go-client) for usage and runnable examples, and the [package documentation on pkg.go.dev](https://pkg.go.dev/github.com/htmlcsstoimage/go-client) for the API reference.

## Direct HTTP example

You can also call the API directly using Go’s standard library:

```go
package main


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


const (
  userID = "your_user_id"
  apiKey = "your_api_key"
)


func main() {
  data := map[string]string{
    "html": "<div class='ping'>Pong ✅</div>",
    "css":  ".ping { padding: 20px; font-family: 'sans-serif'; }",
  }
  reqBody, err := json.Marshal(data)
  if err != nil {
    log.Fatalf("unable to marshal data: %s", err.Error())
  }
  req, err := http.NewRequest("POST", "https://hcti.io/v1/image", bytes.NewReader(reqBody))
  if err != nil {
    log.Fatalf("unable to create new request: %s", err.Error())
  }
  req.SetBasicAuth(userID, apiKey)
  req.Header.Set("Content-Type", "application/json")
  client := &http.Client{Timeout: time.Second * 10}
  resp, err := client.Do(req)
  if err != nil {
    log.Fatalf("request was unsuccessful: %s", err.Error())
  }
  defer resp.Body.Close()
  body, err := io.ReadAll(resp.Body)
  if err != nil {
    log.Fatalf("unable to read response body: %s", err.Error())
  }
  if resp.StatusCode < 200 || resp.StatusCode >= 300 {
    log.Fatalf("API request failed (HTTP %d)", resp.StatusCode)
  }
  fmt.Println(string(body))


  // {"url":"https://hcti.io/v1/image/f1e2762b-1f95-4f99-ab5d-0444b26dfd42"}
}
```

## Need help?

Talk to a human. Email [support@htmlcsstoimage.com](mailto:support@htmlcsstoimage.com) and we’ll help you get started.