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Please do not enter PII or PHI in this form. If you need to share an example, use a sanitized one.

Self-hosted PII and PHI redaction API

Philter: Free, Self-Hosted PII and PHI Redaction API

Philter is open source software that redacts PII and PHI from text. Redacting PII and PHI since 2017, use Philter to maintain HIPAA compliance, meet industry regulations, and leverage your documents for valuable secondary purposes.

Try it live

Try it out! Select one of the industries and click Redact to redact the text.

The redacted text appears here after you click Redact.

Do not enter PHI or PII.

Redaction is much more than *****.

Redaction is much more than finding words and replacing them with asterisks. We're guessing you already knew that, because that's why you're here.

Choose what to redact

Philter can detect and redact many PII and PHI types (names, ages, phone numbers, ID numbers, credit card numbers, VINs, SSNs and ITINs, and more), and you decide which to act on.

Choose how to redact

For every entity type, choose how it's handled: mask it, encrypt it (including format-preserving encryption), replace it with a synthetic value, drop it, or pass it through.

Redact only certain instances

Need to redact only some names, or only zip codes above a population threshold, or only credit cards that pass Luhn validation? Philter's policy engine handles it.

Custom entity types

Define your own dictionaries (project codenames, internal client IDs) and your own identifier patterns (medical record numbers, transaction IDs); Philter treats them as first-class entities alongside the built-in detectors.

Domain-specific lenses

A Philter lens is a specially-trained NLP model. Use the General Purpose lens out of the box, or switch to the Healthcare or COVID-19 lenses for higher accuracy on healthcare PHI.

Built-in audit trail

Every redaction is recorded to a tamper-evident, hash-chained audit log in your own datastore. Query it by date range and export to CSV, so producing compliance evidence of what was redacted and when is a single API call, not an engineering project.

Frequently asked questions

If something here isn’t covered, get in touch and we’ll answer.

How long has Philter been around?
Phileas (the open source library underneath Philter) was first released in 2017. Philter followed as the API layer on top. That makes the Philterd toolkit one of the oldest continuously maintained open source PII redaction engines available, predating the current wave of LLM-wrapper privacy tools by more than six years. The detection engine is a hybrid of purpose-built NLP models and pattern matching, not a prompt sent to a third-party LLM. You can inspect the full commit history, every model, and every line of policy logic on GitHub.
What is Philter?
Philter is an application that redacts protected health information (PHI), personally identifiable information (PII), non-public personal information (NPPI), and other sensitive information from text. Philter processes plain text, plus Microsoft Word and Excel files via its Office add-ins. Philter runs in your private cloud so your sensitive data never has to traverse the public internet. Use Philter's API to process text from virtually any system or process. Philter is open source. Learn more on GitHub.
Does Philter use ChatGPT or other third-party APIs?
No. Philter never transmits your text or documents to any third-party service. Philter can run in a firewalled (or even air-gapped) environment. For example, in AWS you can deploy Philter to a private subnet and use security groups and network ACLs to prevent any outbound traffic from the instance and its subnet, and we recommend doing so to strengthen your overall security posture.
Is Philter open source?
Yes. Philter is open source under the Apache License, Version 2.0. Check out the code, file issues, and contribute on GitHub.
What types of PII, PHI, and sensitive information can Philter redact?
Philter detects many entity types and we add new ones regularly. Among them: Ages · Bitcoin Addresses · US Cities · US Counties · Credit Card Numbers · Custom Dictionaries · Custom Identifiers (e.g. medical record numbers, transaction numbers) · Dates · US Driver's License Numbers · Email Addresses · Hospital Names · IBAN Codes · IP Addresses (IPv4 and IPv6) · MAC Addresses · Passport Numbers · Persons' Names (fuzzy matching, first/last/whole) · Phone/Fax Numbers · Physician Names · SSNs and TINs · Shipping Tracking Numbers · US States · URLs · VINs · US Zip Codes
How does Philter know what to redact?
You create policies that tell Philter which types of PII and PHI to find and how to handle them. A policy lists the entity types (phone numbers, names, etc.), when to act on them, and how to redact them. You can have as many policies as you need and select which one to apply per request. Policies are documented in Philter's User's Guide.
How does Philter identify sensitive information?
Philter uses a variety of methods, including specially trained machine learning models. A Philter lens is a trained model for a specific kind of text. Using a lens that matches your data gives you more accurate results. Philter ships with a General Purpose lens that works across many document types. If you're focused on healthcare PHI, Healthcare or COVID-19 lenses are also available. Contact us for details.
How is Philter deployed?
Philter can be deployed as a container or directly into your cloud from the AWS, Google Cloud, or Microsoft Azure marketplaces in just a few minutes. For container-based deployments, please contact us.
How do I send text to Philter for redaction?
Three options: 1. Call the HTTP API directly. Philter accepts text and returns the redacted text. Generate a client in any language from the Philter OpenAPI specification. 2. Use the Philter CLI for convenient command-line access. 3. Use the open source Java SDK.
What are Philter's accuracy, precision, and recall metrics?
Precision and recall depend greatly on your data. Every dataset is different, so quoting a single F1 score across users would be meaningless. If a vendor cites accuracy without seeing your documents, be very cautious. We'd rather take some representative text from you and spend a few days gathering precision and recall metrics specific to your data, then send those back to you alongside the redacted output.
Is Philter guaranteed to find 100% of all sensitive information?
Philter uses state-of-the-art NLP technology, which is fundamentally non-deterministic. Identification accuracy depends on how similar your text is to the training corpus, how the text is formatted, and how long it is. For that reason, it's important to assess Philter's performance on your own data before relying on it in production. Every detected entity has a confidence score between 0 and 100. The confidence condition in a filter strategy lets you tune detection. For example, confidence > 75 ignores entities the model isn't sure about and only redacts high-confidence matches.
How does Philter compare with Amazon Comprehend, Google DLP, and similar services?
Direct comparisons are tricky because Philter is designed differently. Philter goes beyond identification. It includes disambiguation, ignore lists, value replacement, and anonymization out of the box. The other services may technically support some of these, but only if you build them yourself on top. Philter is also not a managed SaaS API. You deploy it into your environment and call its API over your own network, so your text never has to leave your perimeter. We think that's substantially more secure than handing sensitive text to a third-party API. Finally, Philter is flexible: you can use your own models and you have full control over the filtering pipeline. For a side-by-side breakdown against Amazon Comprehend, Google Cloud DLP, Microsoft Presidio, Private AI, and others, see our comparison page.
What is Philter's license agreement?
Philter is open source software under the Apache License, Version 2.0. The full Philter license agreement is published on this site, and the licensing details are also available on the project repository.

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