# Software Engineer, Platform
**Company:** [Sim](https://hotfix.jobs/companies/sim)
**Location:** San Francisco, CA
**Salary:** $140K-$220K
**Skills:** React, TypeScript, Next.js, WebSockets, Crdts, AWS, Canvas Editors, Real-Time Systems, State Management
**Posted:** 2026-03-02
> Leads the visual platform for building AI agents via drag-and-drop canvas, owning front-end architecture, real-time interactions, and workflow execution bridge. Requires deep React/TypeScript expertise and experience with complex interactive UIs for developers.
## Job Description
## What You'll Do

- Own the Sim visual canvas — the real-time, drag-and-drop workflow editor at the heart of the product
- Architect and build the front-end systems that render, connect, and manage complex agent workflows
- Design the interaction model for how developers create, test, debug, and deploy agents visually
- Build the bridge between visual flows and the underlying execution engine — ensuring what you see is what runs
- Drive performance and responsiveness across the editor, even as workflows grow in complexity
- Shape developer ergonomics and UX patterns across the platform — block configuration, variable wiring, real-time feedback, deployment flows
- Work across the stack in our Next.js monorepo when needed, shipping to production daily
- Set front-end standards for the codebase — component architecture, state management, testing patterns

## What We're Looking For

- Design-minded full-stack engineer with deep **React** and **TypeScript** experience
- Strong sense of product and UX — you care deeply about how things feel, not just how they work
- Experience building complex, interactive UIs — canvas editors, real-time collaborative tools, visual programming environments, or similarly demanding front-end systems
- Track record of shipping polished developer tools or creative tools to production
- Deep understanding of front-end performance — you know how to keep complex interfaces fast and responsive
- High agency and ownership — on a team this small, you define the roadmap as much as you execute it
- Comfort working across the stack in a **Next.js** monorepo; backend work is part of the job

**Nice-to-haves:**
- Experience with real-time systems (**WebSockets**, **CRDTs**, or similar)
- Experience with **AWS** infrastructure
- Contributions to open-source projects
**Apply:** https://hotfix.jobs/jobs/software-engineer-platform-at-sim-330edd29-a227-40c8-b354-25f724eee953
**Canonical:** https://hotfix.jobs/jobs/software-engineer-platform-at-sim-330edd29-a227-40c8-b354-25f724eee953