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Create a Regex Classifier

Audience: Data Governors

Content Summary: In addition to built-in classifiers, Sensitive Data Discovery can use custom classifiers to discover and apply tags to sensitive data. This page details how to create a custom regex classifier. For specific details and examples of other classifiers, see the Create a Custom Dictionary Classifier or Create a Custom Column Name Regex Classifier tutorials.

Use Case: Custom Regex Classifier

Scenario: You've listed Immuta's built-in classifiers for Sensitive Data Detection, but you discover there is no classifier that can automatically detect and tag columns that contain account numbers in your database.

A regular expression (regex) custom classifier allows you to create your own detectors that enable Immuta's Sensitive Data Discovery to find matches based on a regex pattern. For example, if a table contains account numbers in the form of xxxxxxxxx-xxx-x, you could define a regex pattern in a custom classifier to identify and tag these columns. The tutorial below uses this scenario to illustrate creating this classifier.


Attributes of the Custom Regex Classifier

Attributes of all custom classifiers are provided on the Sensitive Data Discovery API page. However, attributes specific to the custom regex classifier are outlined in the table below.

Attribute Description Required
name string Unique, request-friendly classifier name. Yes
displayName string Unique, human-readable classifier name. Yes
description string The classifier description. Yes
type string The type of classifier: regex. Yes
config object Includes config.minConfidence, config.tags, and config.regex. *See descriptions for these below. Yes
minConfidence* number When the detection confidence is at least this percentage, tags are applied. Yes
tags* array[string] The name of the tags to apply to the data source. Note: All tags must start with Discovered.. Yes
regex* string A case-insensitive regular expression to match against column values. Yes

Create a Custom Regex Classifier

  1. Generate your API key on the API Keys tab on your profile page and save the API key somewhere secure. You will include this API key in the authorization header when you make a request to the Immuta API or use it to configure your instance with the Immuta CLI.

  2. Save the custom regex classifier payload in a .json file.

      "displayName": "Account Number Classifier",
      "description": "This classifier identifies account numbers using a regex",
      "type": "regex",
      "config": {
        "regex": "^[0-9]{9}-[0-9]{3}-[0-9]{1}$",
        "minConfidence": 0.5,
        "tags": ["Discovered.account-number"]
  3. Create the classifier using one of these methods:

    Immuta CLI (Inline)

    immuta sdd classifier create ./example-payload.json --output json

    The options you can specify include

    • -h or --help: Get more information about the command.
    • -o or --output json | yaml: Specify the output format.
    • --outputTemplate string: Format the response using a Go template.

    Immuta CLI (File-Based)

    immuta api sdd/classifier -X POST --input ./example-payload.json


    curl \
        --request POST \
        --header "Content-Type: application/json" \
        --header "Authorization: 12345678900000" \
        --data @example-payload.json \
  4. If the request is successful, you will receive a response that contains details about the classifier.

      "createdBy": {
        "id": 1,
        "name": "John",
        "email": ""
      "displayName": "Account Number Classifier",
      "description": "This classifier identifies account numbers using a regex",
      "type": "regex",
      "config": {
        "tags": [
        "regex": "[0-9]{9}-[0-9]{3}-[0-9]{1}",
        "minConfidence": 0.5
      "id": 1,
      "createdAt": "2021-10-14T18:48:56.289Z",
      "updatedAt": "2021-10-14T18:48:56.289Z"

What's Next

Continue to one of the following tutorials:

  • Run Sensitive Data Discovery on Data Sources: Trigger SDD to run on specified data sources.
  • Create a Template: Although only Data Governors can create classifiers, Data Owners can add classifiers to templates, which they then apply to their data sources to override minConfidence or tags for classifiers within the template.