Startup profile · funding coverage
Promptfoo funding, valuation and investors
Open-source LLM evaluation and red-teaming toolkit for enterprise AI safety.
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Funding, valuation & investors
Answer-first snapshotLatest funding
Series A
$18.4M · July 2025
Latest known valuation
Not publicly disclosed
Total disclosed equity funding
$23M
Excludes debt, grants, acquisitions, secondaries, and IPO proceeds.
Current status
private
series a · San Francisco, California, USA
Overview
Promptfoo provides open-source CLI and cloud tools to evaluate LLM outputs: regression tests, red-teaming, prompt comparison, and CI integration. Founded by Ian Webster, it became widely used for RAG and agent testing. a16z led $5M seed (Jul 2024); Insight Partners led $18.4M Series A (Jul 2025) with a16z participating.
Why Promptfoo is interesting
a16z led $5M seed (2024) then joined Insight's $18.4M Series A (2025) — default OSS layer for testing prompts before production AI ships.
Product & use cases
Promptfoo runs eval suites against LLM prompts, compares models side-by-side, automates red-team attacks for jailbreaks, and integrates with GitHub Actions for CI.
- LLM prompt regression testing in CI/CD
- Red-teaming generative AI apps before launch
- Comparing GPT vs Claude vs open models
- RAG pipeline quality evaluation
Key facts
- Series A (Jul 2025): $18.4M led by Insight; a16z participated
- Seed (Jul 2024): $5M led by a16z
- Widely used open-source LLM eval CLI
Funding history (newest first)
Series A
2025-07 $18.4MSource: Read source · promptfoo.dev
Investors in our directory
Funds linked from Promptfoo's profile — open a fund page for stage focus and related deal articles.
Competitive landscape
Edge: Open-source adoption and developer-first CLI before enterprise incumbents shipped eval products.
LLM eval is fast-moving category as enterprises require audit trails. Promptfoo's OSS wedge drives commercial cloud upsell vs proprietary-only rivals.
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Weights & Biases adjacent
ML experiment tracking adding LLM eval.
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Arthur AI direct
Enterprise ML monitoring and LLM eval.
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Humanloop adjacent
Prompt management and evaluation.
Notable stories
- Promptfoo gained GitHub stars rapidly as teams needed something between 'vibe check' and full ML platform for LLM QA.
Industries
Market / IPO context
Editorial / static context — not a live quote.
FAQs about Promptfoo
Practical answers founders, operators, and investors typically search for.
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Editorial note: AI tools assisted with research, structure, or drafting. Venture Capital Tracker retains human editorial responsibility for factual accuracy, relevance, and source quality before publication.