Founding Software Engineer

About Inbox:

Inbox (formerly TweetDM) is building the infrastructure for social selling and communication. We’re starting with X and expanding to every platform where relationships and conversations happen. It’s an all-in-one system to track contacts, conversations, and outreach.

Our users are influencers, startups, and relationship-driven builders (like VCs) who need to manage thousands of touchpoints. Customers have already sent millions of messages through Inbox, and our goal is to scale to a billion searchable messages.

About you:

We're looking for a founding product engineer to help scale the foundation of Inbox. This is not a generic full stack role the only candidates we will consider are those who have:

• Strong backend development skills in TypeScript/Node.js with production experience.
• Comfort building high-throughput messaging systems (tens of thousands of messages per hour).
• Experience working with large, real-time datasets
• An understanding of multiplayer/team-based product challenges (sync across multiple users/screens).
• (Bonus) Familiarity with Cloudflare Durable Objects, distributed infra, or AI-powered messaging systems.

Customers are power users who need to run social selling / communication at scale and we need to build an amazing product to enable this.

In this role you will:

• Help scale our infra to support millions of messages reliably and in real-time.
• Build AI-driven features that make communication faster, smarter, and more personalized.
• Create multiplayer experiences that sync seamlessly across teams and devices.
• Reconcile fragmented user information into a single unified view.
• Work directly with founders and early customers to ship quickly and iterate on what works.

We're especially interested in engineers who have built out beautiful, robust web apps end to end. If there's projects you're proud of please include them in your application!