Senior Software Engineer, Agent Infrastructure and Reliability

Apply on YC · Original job listing

• Role: Engineering / Full stack
• Experience: 6+ years
• Visa: US citizen/visa only
• Skills: Distributed Systems

What we're building

Enterprise marketing still runs through agencies because launching one campaign means coordinating specialists across Marketo, HubSpot, Meta, LinkedIn, CMSs, and a dozen other systems. It takes weeks.

CharacterQuilt uses computer-use agents to do that work inside the software companies already use. A campaign that took three months can now ship in two days. We raised $13M and were one of the fastest-growing companies in YC's P26 batch.

The role

You'll set the architecture and reliability bar for the infrastructure that runs every CharacterQuilt agent.

This is not a narrow platform role. You'll own the system from Postgres and the filesystem through workers, sandboxes, authenticated browsers, and the product state customers see.

What you'll own

• Worker and sandbox orchestration that stays correct through crashes, retries, and timeouts.
• Durable execution, idempotency, recovery, and observability for consequential agent actions.
• Browser profiles, credentials, tenant isolation, and authenticated session reliability.
• The API, CLI, and MCP surfaces around our agent runtime.
• A simpler system and a higher engineering bar as the team grows.

You might be a fit if

• You've owned production distributed systems, developer infrastructure, or browser automation.
• You can debug across application code, databases, queues, networks, and filesystems.
• You want staff-level scope without staff-level distance from the work.