How to detect and redact Personally Identifying Information (PII)

The PII feature can evaluate unstructured text, extract and redact sensitive information (PII) and health information (PHI) in text across several pre-defined categories.

Development options

To use PII detection, you submit text for analysis and handle the API output in your application. Analysis is performed as-is, with no customization to the model used on your data. There are two ways to use PII detection:

Development option	Description
Language studio	Language Studio is a web-based platform that lets you try entity linking with text examples without an Azure account, and your own data when you sign up. For more information, see the Language Studio website or language studio quickstart.
REST API or Client library (Azure SDK)	Integrate PII detection into your applications using the REST API, or the client library available in various languages. For more information, see the PII detection quickstart.

Determine how to process the data (optional)

Specify the PII detection model

By default, this feature will use the latest available AI model on your text. You can also configure your API requests to use a specific model version.

Input languages

When you submit documents to be processed, you can specify which of the supported languages they're written in. if you don't specify a language, extraction will default to English. The API may return offsets in the response to support different multilingual and emoji encodings.

Submitting data

Analysis is performed upon receipt of the request. Using the PII detection feature synchronously is stateless. No data is stored in your account, and results are returned immediately in the response.

When using this feature asynchronously, the API results are available for 24 hours from the time the request was ingested, and is indicated in the response. After this time period, the results are purged and are no longer available for retrieval.

Select which entities to be returned

The API will attempt to detect the defined entity categories for a given document language. If you want to specify which entities will be detected and returned, use the optional piiCategories parameter with the appropriate entity categories. This parameter can also let you detect entities that aren't enabled by default for your document language. The following example would detect only Person. You can specify one or more entity types to be returned.

Tip

If you don't include default when specifying entity categories, The API will only return the entity categories you specify.

Input:

Note

In this example, it will return only person entity type:

https://<your-language-resource-endpoint>/language/:analyze-text?api-version=2022-05-01

{
    "kind": "PiiEntityRecognition",
    "parameters": 
    {
        "modelVersion": "latest",
        "piiCategories" :
        [
            "Person"
        ]
    },
    "analysisInput":
    {
        "documents":
        [
            {
                "id":"1",
                "language": "en",
                "text": "We went to Contoso foodplace located at downtown Seattle last week for a dinner party, and we adore the spot! They provide marvelous food and they have a great menu. The chief cook happens to be the owner (I think his name is John Doe) and he is super nice, coming out of the kitchen and greeted us all. We enjoyed very much dining in the place! The pasta I ordered was tender and juicy, and the place was impeccably clean. You can even pre-order from their online menu at www.contosofoodplace.com, call 112-555-0176 or send email to order@contosofoodplace.com! The only complaint I have is the food didn't come fast enough. Overall I highly recommend it!"
            }
        ]
    }
}

Output:

{
    "kind": "PiiEntityRecognitionResults",
    "results": {
        "documents": [
            {
                "redactedText": "We went to Contoso foodplace located at downtown Seattle last week for a dinner party, and we adore the spot! They provide marvelous food and they have a great menu. The chief cook happens to be the owner (I think his name is ********) and he is super nice, coming out of the kitchen and greeted us all. We enjoyed very much dining in the place! The pasta I ordered was tender and juicy, and the place was impeccably clean. You can even pre-order from their online menu at www.contosofoodplace.com, call 112-555-0176 or send email to order@contosofoodplace.com! The only complaint I have is the food didn't come fast enough. Overall I highly recommend it!",
                "id": "1",
                "entities": [
                    {
                        "text": "John Doe",
                        "category": "Person",
                        "offset": 226,
                        "length": 8,
                        "confidenceScore": 0.98
                    }
                ],
                "warnings": []
            }
        ],
        "errors": [],
        "modelVersion": "2021-01-15"
    }
}

Getting PII results

When you get results from PII detection, you can stream the results to an application or save the output to a file on the local system. The API response will include recognized entities, including their categories and subcategories, and confidence scores. The text string with the PII entities redacted will also be returned.

Service and data limits

For information on the size and number of requests you can send per minute and second, see the service limits article.

Next steps

Named Entity Recognition overview