Staff Software Engineer, Agent Infrastructure and Reliability

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.

Five days a week in Union Square. $250K to $350K base plus 0.5% to 3% equity. We do not sponsor US visas.