> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pictify.io/llms.txt
> Use this file to discover all available pages before exploring further.

# A/B Testing Images

> Test image variants to optimize click-through rates and engagement

# A/B Testing Images

This guide walks you through creating an A/B test experiment, embedding it in your site or emails, tracking events, and completing the test.

## Prerequisites

* A Pictify API key
* At least two templates to test

## Step 1: Create an Experiment

Create an A/B test with two variants:

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.pictify.io/experiments/api \
    -H "Authorization: Bearer $API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "name": "Email Banner CTR Test",
      "type": "ab_test",
      "slug": "email-banner-ctr",
      "variants": [
        {
          "id": "control",
          "name": "Current Design",
          "weight": 5000,
          "templateUid": "tmpl_current123"
        },
        {
          "id": "new-design",
          "name": "New Design",
          "weight": 5000,
          "templateUid": "tmpl_new456"
        }
      ],
      "goalConfig": {
        "type": "click_through",
        "destinationUrl": "https://example.com/landing"
      }
    }'
  ```

  ```typescript Node.js theme={null}
  const experiment = await pictify.experiments.create({
    name: 'Email Banner CTR Test',
    type: 'ab_test',
    slug: 'email-banner-ctr',
    variants: [
      { id: 'control', name: 'Current Design', weight: 5000, templateUid: 'tmpl_current123' },
      { id: 'new-design', name: 'New Design', weight: 5000, templateUid: 'tmpl_new456' }
    ],
    goalConfig: { type: 'click_through', destinationUrl: 'https://example.com/landing' }
  });
  ```

  ```python Python theme={null}
  experiment = pictify.experiments.create(
      name='Email Banner CTR Test',
      type='ab_test',
      slug='email-banner-ctr',
      variants=[
          {'id': 'control', 'name': 'Current Design', 'weight': 5000, 'template_uid': 'tmpl_current123'},
          {'id': 'new-design', 'name': 'New Design', 'weight': 5000, 'template_uid': 'tmpl_new456'}
      ],
      goal_config={'type': 'click_through', 'destination_url': 'https://example.com/landing'}
  )
  ```
</CodeGroup>

The experiment is created in `draft` status.

## Step 2: Start the Experiment

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.pictify.io/experiments/api/exp_abc123/start \
    -H "Authorization: Bearer $API_KEY"
  ```

  ```typescript Node.js theme={null}
  await pictify.experiments.start('exp_abc123');
  ```

  ```python Python theme={null}
  pictify.experiments.start('exp_abc123')
  ```
</CodeGroup>

## Step 3: Embed in Your Content

### Email

```html theme={null}
<!-- Variant image with click tracking -->
<a href="https://api.pictify.io/s/email-banner-ctr/click">
  <img src="https://api.pictify.io/s/email-banner-ctr.png" alt="Special offer" />
</a>

<!-- Tracking pixel for open tracking -->
<img src="https://api.pictify.io/s/email-banner-ctr/pixel.gif" width="1" height="1" />
```

### Website

```html theme={null}
<img src="https://api.pictify.io/s/email-banner-ctr.png" alt="Hero banner" />
```

Each viewer automatically receives a variant based on the weight distribution.

## Step 4: Track Events (Optional)

For server-side or custom tracking:

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.pictify.io/s/events \
    -H "Content-Type: application/json" \
    -H "X-Write-Key: $WRITE_KEY" \
    -d '{
      "event": "conversion",
      "experiment": "email-banner-ctr",
      "variantId": "new-design"
    }'
  ```

  ```typescript Node.js theme={null}
  await fetch('https://api.pictify.io/s/events', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'X-Write-Key': writeKey
    },
    body: JSON.stringify({
      event: 'conversion',
      experiment: 'email-banner-ctr',
      variantId: 'new-design'
    })
  });
  ```
</CodeGroup>

<Warning>
  Always include a write key to prevent third parties from injecting fake events into your experiment.
</Warning>

## Step 5: Complete the Experiment

Once you have enough data, declare a winner:

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.pictify.io/experiments/api/exp_abc123/complete \
    -H "Authorization: Bearer $API_KEY" \
    -H "Content-Type: application/json" \
    -d '{ "winnerVariantId": "new-design" }'
  ```

  ```typescript Node.js theme={null}
  await pictify.experiments.complete('exp_abc123', {
    winnerVariantId: 'new-design'
  });
  ```

  ```python Python theme={null}
  pictify.experiments.complete('exp_abc123', winner_variant_id='new-design')
  ```
</CodeGroup>

After completion, the experiment URL (`/s/email-banner-ctr.png`) serves only the winning variant.

## Tips

1. **Check your quota first**: `GET /experiments/api/quota` shows your plan limits
2. **Run for at least 7 days** to account for day-of-week variations
3. **Use at least 1,000 impressions** per variant before drawing conclusions
4. **Enable auto-optimization** with `banditConfig.enabled: true` for low-traffic tests
5. **Set a fallback image** so the experiment URL works even after the experiment expires