Comparison
FAULTLINE VS. PROMPTFOO
PromptFoo evaluates prompts. Faultline verifies claims. If your team ships AI-generated content to end users, you need verification — not evaluation.
Key differentiator: "PromptFoo evaluates prompts. Faultline verifies claims."
Feature Comparison
A side-by-side breakdown of capabilities across the two tools.
Where Faultline Wins
Four capabilities that PromptFoo does not offer and Faultline ships on day one.
Per-claim reports built in
Every Faultline scan can be exported as a report: each claim, its verdict and its sources. PromptFoo requires you to build this yourself.
A verification layer, not a test harness
Faultline checks up to 8 claims per scan with Google Gemini against live web sources that Faultline finds with Parallel to surface contradictions; on Enterprise, multi-model consensus adds OpenAI and Claude. PromptFoo evaluates prompts and model outputs against the test assertions you write.
Claim-level forensics, not prompt-level metrics
PromptFoo tells you if a response is relevant or faithful. Faultline tells you if the specific claims inside that response are true — with sources.
Verification rules out of the box
Faultline ships with pre-built verification rules covering hallucination patterns, citation errors, and factual drift across domains.
Pricing Comparison
PromptFoo is open source with an enterprise tier. Faultline offers hosted tiers with audit-trail reporting included.
Faultline
- Personal$19/mo
- Pro$49/mo
- EnterpriseCustom
PromptFoo
- Open sourceFree
- EnterpriseCustom pricing
Try Faultline Free
Search-grounded verification pipeline. Personal plan at $19/mo, no credit card required to start. Faultline is in alpha: limits and features may change.