How piighost compares

piighost combines four properties a conversational agent needs. It restores the reply for the user, keeps the same placeholder over the whole conversation, hands the real value to tools, and restores while the reply streams. None of the tools below combines all four. Each one is better than piighost at something else, and its entry says what.

Open a solution to see how it differs from piighost.

Presidio (Microsoft)

	`piighost`	Presidio
Detection	regex, NER or LLM	NER, regex, rules, check digits
What happens to a value	reversible placeholder (memory, Redis or SQL)	mask or encrypted token
Restored for the user	✅	⚠️ by hand (`decrypt`)
Same placeholder over the conversation	✅ per conversation	❌
Real value to tools, placeholder to the LLM	✅	❌
Restored while streaming	✅	❌
Configurable steps after detection	✅ linking, fuzzy matching, expansion, guard rail	⚠️ operators only
Unit processed	text, conversation	text
Hosting	✅ self-hosted	✅ self-hosted
License	MIT	MIT

Better at: validating a format by its check digits, on typed text. piighost can also use it as a detector, with PresidioDetector.

LangChain PII (Python PIIMiddleware)

	`piighost`	LangChain PII
Detection	regex, NER or LLM	regex, validators
What happens to a value	reversible placeholder (memory, Redis or SQL)	mask or hash
Restored for the user	✅	❌
Same placeholder over the conversation	✅ per conversation	❌
Real value to tools, placeholder to the LLM	✅	✅
Restored while streaming	✅	✅
Configurable steps after detection	✅ linking, fuzzy matching, expansion, guard rail	❌
Unit processed	text, conversation	text, conversation
Hosting	✅ self-hosted	✅ self-hosted
License	MIT	MIT

Better at: there is nothing more to install in a LangChain agent. That is enough when the user does not need to read their real values. The JS version (piiRedactionMiddleware) restores the real values for the user, but not while the reply streams.

AWS Comprehend and Azure AI Language

	`piighost`	AWS / Azure
Detection	regex, NER or LLM	machine learning
What happens to a value	reversible placeholder (memory, Redis or SQL)	mask
Restored for the user	✅	❌
Same placeholder over the conversation	✅ per conversation	❌
Real value to tools, placeholder to the LLM	✅	❌
Restored while streaming	✅	❌
Configurable steps after detection	✅ linking, fuzzy matching, expansion, guard rail	❌
Unit processed	text, conversation	text, documents
Hosting	✅ self-hosted	❌ cloud
License	MIT	paid

Better at: models the provider maintains, to mask documents in a cloud already in place. Azure's Conversation mode only detects.

Google DLP

	`piighost`	Google DLP
Detection	regex, NER or LLM	machine learning, predefined types (infoTypes)
What happens to a value	reversible placeholder (memory, Redis or SQL)	stateless encrypted token
Restored for the user	✅	⚠️ through an API call
Same placeholder over the conversation	✅ per conversation	✅ always the same token for a value
Real value to tools, placeholder to the LLM	✅	❌
Restored while streaming	✅	❌
Configurable steps after detection	✅ linking, fuzzy matching, expansion, guard rail	⚠️ transformations
Unit processed	text, conversation	text, dataset
Hosting	✅ self-hosted	❌ cloud
License	MIT	paid

Better at: transforming whole datasets in Google Cloud.

pii-redactor

	`piighost`	pii-redactor
Detection	regex, NER or LLM	regex, NER
What happens to a value	reversible placeholder (memory, Redis or SQL)	reversible token (vault)
Restored for the user	✅	✅
Same placeholder over the conversation	✅ per conversation	✅ per session
Real value to tools, placeholder to the LLM	✅	❌
Restored while streaming	✅	✅
Configurable steps after detection	✅ linking, fuzzy matching, expansion, guard rail	❌
Unit processed	text, conversation	text, conversation
Hosting	✅ self-hosted	✅ self-hosted
License	MIT	MIT

Note: it is the closest to piighost. It lacks the real value to tools and the configurable steps.

Detection-only models (spaCy, GLiNER, Piiranha)

Find the data without replacing or restoring it.
Building blocks rather than competitors. piighost uses them as detectors, Piiranha through TransformersDetector.

Dataset anonymizers (ARX, Amnesia)

Transform a whole table with k-anonymity or differential privacy.
The result is anonymous and irreversible, where piighost is reversible.
Better at: publishing or sharing a dataset. Not made for a live conversation.

See Limitations for what piighost does not do, and the reasoning behind these choices.