Overview
HarnessRouter is an AI agent backend platform that lets you bring the world's best AI agents (Codex, Claude Code, Hermes) into your app with a single API. It handles the heavy lifting: sandboxes, orchestration, retries, cost controls, and maintenance. You get finished work—code, files, videos, games—out of the box. It's backed by Y Combinator and trusted by medical research institutions and healthcare companies.
Chert is "Vapi for FaceTime," enabling you to build and deploy interactive AI video agents that can answer and place FaceTime calls. It uses the caller's camera context to understand visual problems, making it ideal for remote support, field service, telehealth intake, and guided onboarding. Currently in private preview.
Feature Comparison
| Feature | HarnessRouter | Chert |
|---|---|---|
| Core Function | Runs AI agent backends via one API, delivering artifacts | Deploys AI video agents for FaceTime calls |
| Primary Interface | API-first | FaceTime line |
| Target Use Cases | Code generation, document creation, video production | Remote support, field service, telehealth |
| Agent Types | Codex, Claude Code, Hermes, Pi (soon) | Customizable assistant |
| Output | Structured artifacts (diffs, files, images) | Real-time video interaction |
| Deployment | 3 steps: AGENTS.md, describe, API key | 3 steps: prompt, persona, line |
| Control & Monitoring | Step-by-step tracing, cost controls | Browser preview, configurable settings |
| Availability | Generally available | Private preview |
Pricing
HarnessRouter offers a 7-day free trial, then monthly platform plans: Developer, Production, and Scale. Plans include credits for production work; additional usage is billed from a top-up balance with budgets and hard caps.
Chert does not publicly disclose pricing. It's in a controlled private preview, and interested users can book a demo. Pricing likely depends on usage and features, but specifics are not available.
Pros and Cons
HarnessRouter
Pros:
- One API for multiple leading AI agents
- Handles backend complexity (sandboxes, orchestration, retries)
- Structured outputs for easy integration
- Trusted by top institutions
- Flexible harness swapping
Cons:
- May be overkill for simple chat features
- Requires understanding of agent concepts
- Pricing may be higher for small-scale use
Chert
Pros:
- Unique video-first approach with camera context
- Simple deployment
- Browser preview for testing
- Ideal for visual problem-solving
- Supports inbound and outbound calls (bounded)
Cons:
- Not generally available yet
- Limited to FaceTime platform
- No artifact generation
- Less flexible for non-video use cases
Verdict
Choose HarnessRouter if you need to integrate AI agents that produce tangible artifacts (code, files, videos) into your app with a robust backend. Choose Chert if your use case is visual, real-time support via FaceTime, and you're comfortable with a private preview. Both are powerful but serve different niches.