navi-sanitize¶

Deterministic input sanitization for untrusted text --- invisible characters, homoglyphs, and encoding tricks, handled before your code sees them. Zero dependencies, no ML. Legitimate Unicode preserved by design.

navi-sanitize removes invisible attacks from untrusted text before it reaches your application. It doesn't detect attacks --- it removes them. Implements the pipeline recommended by the OWASP LLM Prompt Injection Prevention Cheat Sheet.

Get Started API Reference

See the invisible¶

evil = "system\u200b\u200cprompt"  # looks like "systemprompt" but has 2 hidden chars
len(evil)           # 14 (not 12!)
clean(evil)         # "systemprompt" — hidden chars stripped

Features¶

• 6-stage pipeline --- null bytes, invisible characters, NFKC normalization, homoglyph replacement, re-NFKC for idempotency, pluggable escaper
• OWASP aligned --- implements the NFKC + zero-width + control character sanitization recommended by the LLM Prompt Injection Prevention Cheat Sheet
• Only maintained option --- both confusable_homoglyphs and homoglyphs are archived; navi-sanitize is the only maintained Python library covering homoglyph replacement
• Deterministic --- same input always produces the same output; no probabilistic models, no heuristics
• Zero dependencies --- Python 3.12+ stdlib only; no third-party dependency risk
• Pluggable escapers --- built-in Jinja2 and path traversal escapers; write your own in three lines
• Recursive sanitization --- walk() sanitizes every string in nested dicts and lists
• Transparent logging --- warnings include counts ("Stripped 3 invisible character(s)")
• Opt-in utilities --- decode_evasion() for nested encoding, detect_scripts() / is_mixed_script() for mixed-script analysis --- not enabled by default

Quick Start¶

pip install navi-sanitize

from navi_sanitize import clean

clean("Неllo Wоrld")      # "Hello World" — Cyrillic Н/о replaced
clean("price:\u200b 0")   # "price: 0" — zero-width space stripped
clean("file\x00.txt")     # "file.txt" — null byte removed

Documentation¶

Links¶

• GitHub Repository
• Issue Tracker
• PyPI