Principal Software Engineer, Platform (DevEx)

Ready to be a Titan?
ServiceTitan is building the Developer Platform for enterprise-scale SaaS. DevEx is a newly formed, lean, highly agile team (3–4 people) building AI-enabled platform infrastructure — pioneering AI-assisted development tools and coding agent runtimes (like Codex) to help engineering teams operate at "AI speed."

This is a Principal Engineer role per ServiceTitan's engineering leveling framework: 10+ years of experience, SME & Systems Design Expert level, with broad R&D impact and an 18-month planning horizon. You are not just building within DevEx — you're setting technical direction that other teams and eventually the APEX platform build against.
 

What You'll Build

• AI-Native Tooling: Agent orchestration layers, harnesses, and LLM reasoning loops — infrastructure other engineers will treat as the reference implementation for how ServiceTitan builds with coding agents.

• Environments, Build & CI/CD, Developer Portal, Guardrails & Compliance, Velocity Harness — the full DevEx platform surface, where your architectural calls set the pattern others follow.

What You'll Do

• Domain Expertise & Influence: Proactively identify where your expertise on coding-agent infrastructure could help teams across R&D, not just within DevEx — and contribute to the wider industry conversation on agent-runtime architecture.

• Delivery: Deliver complete, comprehensive system designs and lead autonomous delivery of the projects that come from them, in partnership with R&D peers. Remove barriers that are widely felt across the engineering org, not just your pod.

• Independence & Decision Making: Operate self-directed and unsupervised. Act as the key technical consultant on agent-runtime architecture across multiple teams; your judgment and timeliness on hard calls is what people rely on.

• Complex System Understanding: Anticipate technical problems before they surface in major platform initiatives; identify ServiceTitan's technology needs on a 1–3 year horizon for AI-native developer tooling and drive the milestones to get there.

• Leading by Example: Your work (harness code, orchestration patterns, agent-safety guardrails) becomes the thing other engineers copy to hit the quality bar you've set.

• Mentor and raise the technical bar for engineers at Staff level and below on the team.

What You'll Bring

• 15-20+ years of software engineering experience, with recent (last 6–12 months) hands-on work building coding-agent-runtime infrastructure — agent orchestration, harnesses, or LLM reasoning loops. This is a hard filter: process automation or AI-assisted code review experience does not meet this bar.

• A track record consistent with Principal-level scope: technical decisions and architecture that other teams and orgs build on, not just your own team's roadmap.

• Deep experience with build systems, CI/CD, or internal developer platforms shipped and operated in production at real scale.

• Comfort setting direction with minimal oversight — this is a small, high-trust team; you're expected to define the plan, not receive it.

• Strong instincts for environment safety (RBAC, secrets management, compliance gates) as applied to autonomous or semi-autonomous coding agents specifically.
   

Preferred Experience

• Prior experience where coding agents are already core to daily engineering workflow, not a pilot.

• Experience representing engineering direction externally (blog posts, conference talks) or influencing practice change across an org.

Be Human With Us:
Being human isn’t about checking every box on a list. It’s about the experiences we have, people we meet, and the perspectives we share. So, if you have the skills but are hesitant to apply because of your background, apply anyway. We need amazing people like you to help us challenge the conventional and think differently about the problems that we’re solving. We’re in this together. Come be human, with us. 

Use of AI Technology:

We use technology, including automated and AI-assisted tools, to support certain aspects of our recruitment process. These tools are designed to improve efficiency and enhance the candidate experience. AI tools are not used to make hiring decisions; all hiring decisions are made by our hiring teams.

What We Offer:

When you join our team, you’re not just accepting a job. You’re making a career move. Here’s how we’ll support you in doing some of the most impactful work of your career:

• Flextime, recognition, and support for autonomous wor