HarnessRouter vs sleek.design: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of HarnessRouter and sleek.design — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
HarnessRouter
HarnessRouter
One API to run Codex, Claude Code, Hermes and other coding agents as your product backend — Y Combinator backed.
Key features
- Unified Agent API: Route to Codex, Claude Code, Hermes, Pi and other coding/autonomous agents through one endpoint
- Managed Runtime: Per-run sandbox, sessions, streaming, retries, timeouts, and permissions handled for you
- Artifact Delivery: Agents return files, code, videos, documents and other real artifacts to end users
- Execution Tracing: Step-by-step event timeline with tool calls, file changes, and agent messages for every run
- Per-Harness Settings: Configure model, tools, MCP, skills, and guardrails per harness
- Cost Controls: Budgets, alerts, and hard caps so production usage stops at your limit not your bill
- MCP Support: Bring your own MCP servers and skills into each harness
- Auto Upgrades: Platform handles upgrades, fixes, and maintenance of the agent runtimes
Best for
- Ship a website or app builder where users describe a product and get generated code/media
- Embed a digital employee that runs long-running tasks inside your SaaS
- Build model evaluation, legal, ops, or planning agents backed by frontier coding models
- Add an AI feature that produces videos, games, docs, or codebases as artifacts for end users
- Skip building sandboxing, streaming, retries, and permissions in-house
- Give internal teams a governed way to run Codex or Claude Code against production data
- Deploy an agent backend with production credits and hard cost caps
sleek.design
Sleek
AI-powered mobile app mockup generator that creates iOS and Android app designs instantly without a designer.
Key features
- Instant Mockup Generation: Converts text prompts or app ideas into polished iOS and Android screen designs within seconds, enabling rapid visualization of concepts.
- Cross-Platform Output: Produces both iOS and Android style mockups, ensuring platform-consistent layouts and components for each target OS.
- Chat-Based Iteration: Supports iterative refinement by allowing users to refine designs through conversational inputs, speeding up the design iteration loop.
- Figma & Code Export (Export Capability): Provides options to export designs to Figma or generate developer-friendly assets/code snippets for easier handoff (noted in third-party sources).
- Template and Variation Generation: Generates multiple layout variations and templates from a single idea to explore alternative UI directions quickly.
- No-Designer Workflow: Enables non-designers to produce high-quality app screens without hiring a designer, reducing time and cost in early-stage prototyping.
- Generate mobile app mockups from text prompts or ideas
- Support for iOS and Android screen designs and templates
- Chat-driven iteration to refine designs interactively
- Export designs to Figma
- Export design assets or code (export to code mentioned)
- Web-based interface — no local installation required
- Aimed at rapid prototyping and eliminating need for a dedicated designer
- Free access / Freemium availability as indicated on site
- No public API or official documentation referenced in provided content
Best for
- Early Concept Validation: Founders and product managers can turn an app idea into visual screens instantly to validate concepts with stakeholders or users.
- Rapid Prototyping for MVPs: Teams can generate initial screen designs for minimum viable products to accelerate development planning and user testing.
- Design Iteration without Specialists: Non-designers can iterate UI layouts and copy via chat-driven refinements to explore multiple directions quickly.
- Handoff to Engineering or Designers: Exported Figma files or code snippets streamline collaboration by providing ready assets for developers or detail work by designers.
- User Testing and Feedback: Create varied screen versions quickly to run A/B tests or user interviews to collect early usability feedback.
- Rapidly create UI screens and prototypes from product ideas
- Iterate on app visual designs with non-designers via chat
- Export screens to Figma for further design work or handoff
- Generate starter code or assets for developer handoff
- Create demo screens for pitches, user testing, or stakeholder reviews