Fabraix

Fabraix builds red-teaming AI agents that continuously find security vulnerabilities in customer-facing AI systems. Its flagship product, Nyx, autonomously discovers exploits across chat, voice, browser, and coding agents without needing source-code access, drawing on a library of more than 10,000 jailbreaks and adaptive attack strategies that pursue promising approaches across hundreds of interactions. Fabraix also created ACE (Adversarial Cost to Exploit), a game-theoretic benchmark that measures AI security by the cost of a successful attack, enabling continuous, lower-cost vulnerability testing that re-assesses systems with each update. Fabraix is a Y Combinator (Summer 2026) company. This profile is maintained by the API Evangelist network; no public API, developer documentation, or machine-readable surface has been published by Fabraix at this time.

Fabraix is profiled on the APIs.io network. Tagged areas include Company, AI Security, Red Teaming, AI Agents, and Adversarial Verification.

Fabraix’s developer surface includes engineering blog and 3 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

3.0/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-10-17 · rubric v0.24.0

0 APIs

Company AI Security Red Teaming AI AgentsAdversarial VerificationCybersecurity LLM Security Y Combinator

Kin Score

Kin Score How this is scored →
scored 2026-10-17 · rubric v0.24.0

Composite quality — 3.0/100 · minimal

Contract Quality 0.0 / 21

Developer Ergonomics 0.4 / 17

Access Clarity 0.0 / 17

Operational Transparency 0.0 / 11

Contract Governance 0.0 / 10

Discoverability 4.1 / 9

Regulatory Posture 0.0 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/fabraix: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Resources

Company 2

The organization behind the API

Blog

Blog

Website

Website

Other 2

Properties that don't map to a standard resource type

CompanyProfile

CompanyProfile

Source (apis.yml)

aid: fabraix
name: Fabraix
description: Fabraix builds red-teaming AI agents that continuously find security vulnerabilities in customer-facing AI systems.
  Its flagship product, Nyx, autonomously discovers exploits across chat, voice, browser, and coding agents without needing
  source-code access, drawing on a library of more than 10,000 jailbreaks and adaptive attack strategies that pursue promising
  approaches across hundreds of interactions. Fabraix also created ACE (Adversarial Cost to Exploit), a game-theoretic benchmark
  that measures AI security by the cost of a successful attack, enabling continuous, lower-cost vulnerability testing that
  re-assesses systems with each update. Fabraix is a Y Combinator (Summer 2026) company. This profile is maintained by the
  API Evangelist network; no public API, developer documentation, or machine-readable surface has been published by Fabraix
  at this time.
url: https://raw.githubusercontent.com/api-evangelist/fabraix/refs/heads/main/apis.yml
deliveryModel:
  model: unknown
  open_source: false
  commercial: false
  callable_host: false
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - none
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://fabraix.com/og.png
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
x-tier: stub
x-tier-reason: portfolio-lead
x-batch: Summer 2026
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-10-06'
tags:
- Company
- AI Security
- Red Teaming
- AI Agents
- Adversarial Verification
- Cybersecurity
- LLM Security
- Y Combinator
apis: []
common:
- url: https://fabraix.com/blog
  type: Blog
- type: Website
  url: https://fabraix.com
- type: X
  url: https://x.com/fabraixhq
- type: CompanyProfile
  url: https://www.ycombinator.com/companies/fabraix
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

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