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

# Replace Custom Regex Patterns

> Redact custom patterns with Regex in Portkey.

For more granular control over pattern redaction, you can create custom patterns using Portkey's **Regex Match** guardrail with redaction capabilities. This allows you to define specific regex patterns for sensitive information unique to your use case.

### Setting Up Custom Regex Patterns

<Frame>
  <img src="https://mintcdn.com/portkey-docs/QKXLB-54q6gEhIad/images/guardrails/regex.png?fit=max&auto=format&n=QKXLB-54q6gEhIad&q=85&s=5557c90d78352ee9295bf1e18030fd92" width="1078" height="484" data-path="images/guardrails/regex.png" />
</Frame>

1. **Navigate to Guardrails**: Go to the `Guardrails` page and click `Create`

2. **Select Regex Match**: Choose the "Regex Replace" guardrail from the BASIC category

3. **Configure the Pattern**:
   * **Regex Rule**: Enter your regex pattern to match specific data (e.g., `\b\d{3}-\d{2}-\d{4}\b` for SSN patterns)
   * **Replacement Text**: Define what to replace matches with (e.g., `[REDACTED]`, `*****`, `[SSN_HIDDEN]`)

4. **Save the Guardrail**: Name your guardrail and save it to get the associated Guardrail ID

### Common Regex Patterns for Sensitive Data

| Pattern Type           | Regex Pattern                                        | Replacement Example |
| ---------------------- | ---------------------------------------------------- | ------------------- |
| Credit Card            | `\b\d{4}[- ]?\d{4}[- ]?\d{4}[- ]?\d{4}\b`            | `[CREDIT_CARD]`     |
| Social Security Number | `\b\d{3}-\d{2}-\d{4}\b`                              | `[SSN_REDACTED]`    |
| Phone Numbers          | `\b\d{3}[-.]\d{3}[-.]\d{4}\b`                        | `[PHONE_HIDDEN]`    |
| Email Addresses        | `\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}\b` | `[EMAIL_REDACTED]`  |
| Custom Employee IDs    | `EMP-\d{6}`                                          | `[EMPLOYEE_ID]`     |

### Adding to Your Config

Once you've created your custom regex pattern guardrail, add it to your Portkey config:

```json theme={"system"}
{
  "before_request_hooks": [
    {"id": "your-guardrail-id"}
  ],
  "after_request_hooks": [
    {"id": "your-guardrail-id"}
  ]
}
```

<Note>
  You can add the same guardrail to both `before_request_hooks` (input guardrails) and `after_request_hooks` (output guardrails) to scan and redact regex patterns in both user inputs and LLM responses.
</Note>

### Example Implementation

<Tabs>
  <Tab title="NodeJS">
    ```js theme={"system"}
    const portkey = new Portkey({
        apiKey: "PORTKEY_API_KEY",
        config: "pc-***" // Config with custom regex pattern redaction
    });

    const response = await portkey.chat.completions.create({
        model: "@your-model-slug",
        messages: [
            {
                role: "user",
                content: "My SSN is 123-45-6789 and credit card is 4532-1234-5678-9012"
            }
        ]
    });
    ```
  </Tab>

  <Tab title="Python">
    ```py theme={"system"}
    portkey = Portkey(
        api_key="PORTKEY_API_KEY",
        config="pc-***" # Config with custom regex pattern redaction
    )

    response = portkey.chat.completions.create(
        model="@your-model-slug",
        messages=[
            {
                "role": "user",
                "content": "My SSN is 123-45-6789 and credit card is 4532-1234-5678-9012"
            }
        ]
    )
    ```
  </Tab>
</Tabs>

With the custom regex guardrail configured, the input would be automatically transformed to:

```
"My SSN is [SSN_REDACTED] and credit card is [CREDIT_CARD]"
```