Fabraix vs Relay: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Fabraix and Relay — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
Fabraix
Fabraix
An adversarial staging environment and open playground to find gaps in AI agents through live red-teaming and verification.
Key features
- Live Adversarial Playground: Deploys fully functional AI agents in live challenge environments so researchers and attackers can probe real capabilities rather than toy or mocked scenarios.
- Published System Prompts: System prompts and agent configurations are published openly to ensure transparency and reproducibility of challenges and defenses.
- Versioned Challenge Configs: Challenge definitions and configuration files are stored and versioned in public repositories, enabling traceability and collaborative iteration on tests and fixes.
- Autonomous Red‑Teaming Agents: Provides or links to autonomous agents and tooling that systematically probe target systems to discover failure modes and bypasses.
- Exploit Documentation and Remediation Sharing: When a technique succeeds, the winning method is documented and shared so defenders can learn common weaknesses and implement fixes.
- Community Contribution Model: Encourages external contributors to submit new challenges, attacks, and mitigations to expand coverage and collective understanding.
- Open-Source Repositories and Licensing: Maintains public GitHub repositories (Playground and related tools) with code, challenges, and license files to support adoption and auditing.
- Runtime Security Focus: Orients testing and tooling toward protecting live agent behavior and interactions, not just static model evaluation.
- Live deployment of AI agents for real-world adversarial testing
- Publicly published system prompts and versioned challenge configurations
- Community-driven challenges with documented winning techniques
- Open-source repository containing frontend, challenge configs, and tooling
- Ability to reproduce attacks and defenses for shared learning
- Designed to surface runtime vulnerabilities and failure modes
Best for
- Pre-release Red-Teaming: Run live adversarial challenges against an AI agent prior to product launch to identify prompt-injection, data-exfiltration, or policy-bypass vulnerabilities.
- Security Research and Failure-Mode Analysis: Researchers use the Playground to reproduce, analyze, and document novel agent attacks and their root causes.
- Defensive Engineering and Patch Verification: Developers apply documented winning techniques to validate fixes and confirm that mitigations prevent previously successful exploits.
- Benchmarking Defenses: Operations teams compare different defense strategies or system-prompt configurations against the same community challenges to evaluate robustness.
- Training Security Teams: Security engineers and incident responders practice detection and mitigation in realistic, live-agent scenarios to build operational readiness.
- Community Knowledge Sharing: Open publication of challenges and solutions enables cross-organization learning and dissemination of best practices for agent runtime safety.
- Automated Vulnerability Discovery: Use the provided autonomous probing agents to continuously scan deployed agents for regressions or new vulnerabilities as code and prompts evolve.
- Security validation and hardening of autonomous agents before production rollout
- Red-team exercises to discover prompt- and runtime-based bypasses
- Research and education on agent failure modes and defenses
- Auditing agent behavior by reproducing attacks from community-documented challenges
R
Relay
Relay
AI phone receptionist that builds itself from a business's website to answer every call and book, reschedule, or cancel appointments 24/7.
Key features
- One-Click Build: Paste a website and Relay drafts the agent profile, knowledge base, prompt, and call wiring in about 38 seconds.
- 24/7 Call Answering: Picks up every call day or night in the caller's local time, with no voicemail or hold music.
- Real Calendar Booking: Checks live availability and writes appointments, reschedules, and cancellations directly to the business's existing booking system.
- Booking Integrations: Connects to 7+ systems including Google Calendar, Square, Calendly, Outlook, Housecall Pro, Workiz, and Vagaro with one sign-in.
- Grounded Answers: Answers caller questions from the business's own facts and knowledge base rather than guessing.
- No-Config Setup: Requires no dashboards, prompt engineering, or manual call-flow building.
Best for
- Missed-Call Recovery: Capture bookings from calls that would otherwise ring out when staff are busy or closed.
- Appointment-Based Businesses: Let salons, clinics, and home-service providers automate booking, rescheduling, and cancellations by phone.