Philter

Windows · Linux · Self-hosted · API · paid plans from $8.33/mo

Freedom report

Two barsScore 6.5

  • Free tierA free tier is on its own pricing page
  • Open codeNo open-source code on record
  • Runs widely2 of 6 device platforms
  • DocumentedPlans, terms and facts published

Philter is open source software for detecting and redacting personally identifiable and protected health information in text. Users can choose to mask, encrypt, replace detected values with synthetic ones, remove them, or leave them unchanged. Policies, custom dictionaries, and identifier patterns can be configured for items such as medical record numbers and transaction IDs. Its General Purpose, Healthcare, and COVID-19 NLP lenses address different types of text. Philter provides an HTTP REST API, a Java SDK, and an OpenAPI specification for generating clients in other languages. It can run in a private environment or through AWS, Google Cloud, and Microsoft Azure marketplaces. The maker says text stays in the customer's environment, including in firewalled or air-gapped setups. Redaction requests are recorded in a tamper-evident, hash-chained audit log that can be queried and exported to CSV. Detection is probabilistic, so results should be checked against an organization's own data before production use. The open source toolkit is free; commercial desktop use costs 100.00 USD per year per user.

Who it is for

Philter may suit healthcare, finance, legal, government, and AI teams that need redaction in APIs or data pipelines. It also suits teams that want to configure policies and run processing in their own environment.

What is good

  • Supports masking, encryption, synthetic replacement, and removal.
  • Custom policies and identifier patterns can be configured.
  • Audit logs can be queried and exported to CSV.
  • Runs in customer environments, including air-gapped setups.

What to know first

  • Detection is probabilistic and needs validation before production use.
  • Community support applies to the open source toolkit.
  • Commercial desktop use costs 100.00 USD per year per user.

Freedom251 review

Philter: the full review

Philter offers configurable text redaction with private deployment options and audit logging. Its probabilistic detection makes validation against your own data an important step before production use.

Philter is open-source redaction software for teams handling sensitive text and documents, especially those integrating safeguards into APIs or data pipelines. Its configurable controls and private deployment options are strong fits for regulated work; probabilistic detection makes validation against your own data essential.

Overview

Philter detects personally identifiable and protected health information, then lets users decide how to treat each match: mask it, encrypt it, replace it with a synthetic value, drop it, or pass it through. This flexibility suits workflows that need more than simple removal, but it puts responsibility on teams to define suitable policies and check their results.

Users can create policies, dictionaries, and identifier patterns for items such as medical record numbers and transaction IDs. General Purpose, Healthcare, and COVID-19 NLP lenses offer distinct starting points for different text. Because detection is probabilistic, Philter is a poor choice for production use without validation on the organization’s own data.

Key features

An HTTP REST API, Java SDK, and OpenAPI specification support integration into applications and pipelines. Automated detection and batch processing cover both recurring data flows and larger jobs. OCR redaction and support for PDF, DOCX, XLSX, CSV, TXT, RTF, EML, and MSG make Philter relevant beyond plain text.

Philter can run in a customer-controlled environment, including firewalled or air-gapped deployments, or be deployed through AWS, Google Cloud, and Microsoft Azure marketplaces. The maker says text stays in the customer’s environment rather than being sent to third-party services. That is a meaningful advantage for sensitive workloads, though deployment still requires an environment the team can operate.

Redaction requests are recorded in a tamper-evident, hash-chained audit log in the customer’s datastore; teams can query the log and export it to CSV. The products are released under Apache 2.0, with source code on GitHub for inspection and self-building. The open-source toolkit has community support through documentation and GitHub issue trackers; commercial licenses add direct support.

Pricing

The personal and evaluation Philter Desktop plan costs 0.00 USD per free. It provides full on-device redaction for individual, non-commercial, and evaluation use, with community support on GitHub. It is the no-cost route for trying the desktop workflow, but does not cover commercial use.

The open source toolkit costs 0.00 USD per free and is self-hosted under Apache 2.0, with no license keys or usage caps. It is the strongest fit for teams able to run and maintain their own deployment; it does not include commercial review. For commercial desktop use, Philter Desktop costs 100.00 USD per year, billed $100 USD per user / year. That per-user subscription includes direct creator support and updates, maintenance releases, and upgrades during the subscription. Choose it when a supported commercial desktop license matters; its annual per-user price is less suitable for large groups seeking a single shared license.

The pricing model is freemium, with paid plans from $0.49, but the commercial desktop plan is priced separately at 100.00 USD per year.

Platforms

Philter supports API, Linux, self-hosted, and Windows deployments. Its hybrid deployment options accommodate both locally operated systems and cloud marketplace deployment. OCR, batch processing, and the listed document formats make it useful where redaction must fit into existing document workflows as well as text pipelines.

Who it's for

Philter is aimed at healthcare, finance, legal, government, and AI workloads, including teams adding redaction to APIs and data pipelines. It is best suited to organizations that need policy-level control, audit records, and the option to keep processing inside their own environment. Teams that need a turnkey service without responsibility for policy design or accuracy validation should look elsewhere.

Pros and cons

  • Configurable treatment of matches: masking, encryption, synthetic replacement, dropping, or passing through can support different handling rules.
  • Private deployment and audit trail: customer-environment processing and hash-chained logs suit sensitive workflows that need traceability.
  • Broad integration and document support: REST, Java, OpenAPI, batch processing, OCR, and multiple file formats cover varied pipelines.
  • Production accuracy needs validation: probabilistic detection means teams must assess results against their own data before relying on it.
  • Self-hosting entails operational work: the no-cap toolkit is attractive to capable teams, but its deployment model is not a managed-service substitute.

Alternatives

For a broader comparison, see Document Redaction Software.

Choose BleachPDF for a free tool that runs on your own Linux or macOS computer without subscriptions. Its platform scope is narrower than Philter’s API and self-hosted options.

PDFRedaction is a web alternative with a free plan for registered users capped at 10 documents per day; its stated features include AI detection, OCR, image redaction, and local processing.

PineThink Redact suits macOS or Windows users who want single-document personal redaction free, or a 14-day trial before its 6.99 USD per month Premium plan.

PrivacyScrubber is a web-based freemium option with a free tier capped by character, PDF-page, and upload limits.

GroupDocs.Redaction is a broad-platform document-processing alternative for readers comparing SDK options.

Redact PDF AI offers a $5 prepaid credit option for 50 pages, usable for 30 days, for readers who prefer a limited one-off purchase to a recurring plan.

Docuflair Redact is a paid alternative with a Basic plan at 299.00 EUR per month, net, with annual billing and a 12-month minimum term.

Excise is another free option for Linux, macOS, and Windows.

Verdict

Choose Philter if your team needs configurable text redaction, auditability, and the ability to keep processing in its own environment, particularly in regulated or data-sensitive workflows. Its open-source, no-cap toolkit is compelling for teams prepared to operate it. Look elsewhere if you need dependable production detection without first validating results on your own data, or a fully managed workflow.

Philter plans and pricing

All plans
Philter Desktop — Personal & evaluation Free Individual, non-commercial, and evaluation use · Full on-device redaction · Community support on GitHub philterd.ai · 2 Oct 2026
Open source toolkit Free Self-hosted · Apache 2.0 · No license keys · No usage caps · No commercial review philterd.ai · 2 Oct 2026
Philter Desktop — Commercial $100/yr $100 USD per user / year Per user · Commercial use · Direct creator support · Updates, maintenance releases, and upgrades during subscription philterd.ai · 2 Oct 2026

Compared on document redaction software

Free plan
Yes
Deployment
hybrid
OCR redaction
Yes
Automated detection
Yes
Batch processing
Yes
Audit trail
Yes
Input formats
PDF, DOCX, XLSX, CSV, TXT, RTF, EML, MSG

Best Philter alternatives

See all 20