Principal Software Engineer - Agent Builder - Search in London

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter.

What is The Role:

Elastic is building Agent Builder, a conversational platform that connects production agents to real customer business data in Elasticsearch. As a Principal Engineer, you will set technical direction and drive the Kibana backend architecture for the agentic platform: streaming APIs, secure tool execution, session and memory persistence, retrieval and citations contracts, and evaluation telemetry. Your influence will extend beyond a single feature, shaping service boundaries, reliability posture, and standards that other solutions build on.

What You Will Be Doing:

• Own the architecture for chat back‑end services (Node/TypeScript), defining service boundaries, data contracts, and scalability targets.
• Lead cross‑team design reviews; author ADRs and RFCs that become reference standards for AI‑chat and ingestion work.
• Build and harden event‑driven pipelines that capture chat telemetry, evaluation traces, and LLM feedback loops; expose them via self‑service analytics endpoints.
• Champion reliability—define error budgets, introduce testing strategy, and steer incident‑response playbooks for conversational workloads.
• Mentor senior and Junior engineers; develop their system‑design skills and foster a high‑trust, low‑ego culture.
• Partner with Product, Design, and Data Science to translate ambiguous goals (e.g., “multi‑step reasoning with tool calling”) into incremental, testable action items.
• Represent Elastic in open‑source AI communities (LangGraph/LangChain, MCP/A2A) through design proposals, blog posts, and conference talks.

What You Bring:

• Articulate and “low‑ego” people who want to grow as part of a team.
• 10+ years building distributed, production SaaS services—at least 5 years leading large‑scale Node/TypeScript or similar back‑end stacks.
• Deep expertise in distributed systems fundamentals—shard routing, consensus, eventual consistency, back‑pressure, and circuit‑breaker patterns.
• Demonstrated success designing high‑throughput, low‑latency APIs (gRPC / REST / WebSocket)—including streaming responses and resumable sessions.
• Hands‑on experience with observability: OpenTelemetry, log/metric pipelines, synthetic checks, and SLO dashboards.
• Exposure to LLM tooling (LangChain/LangGraph, OpenAI function calls, vector‑search, RAG orchestration) and enthusiasm for advancing GenAI architectures.
• Clear, persuasive written communication—your ADRs and RFCs set the standard others emulate.

Nice‑to‑have: contribution history to Kibana or other large SPAs; ability to prototype front‑end dashboards when it unblocks back‑end work.

Additional Information – We Take Care of Our People:

As a distributed company, diversity drives our identity. Whether you’re looking to launch a new career or grow an existing one, Elastic is the type of company where you can balance great work with great life. Your age is only a number. It doesn’t matter if you’re just out of college or your children are; we need you for what you can do.

We strive to have parity of benefits across regions, and while regulations differ from place to place, we believe taking care of our people is the right thing to do.

• Competitive pay based on the work you do here and not your previous salary.
• Health coverage for you and your family in many locations.
• Ability to craft your calendar with flexible locations and schedules for many roles.
• Generous number of vacation days each year.
• Increase your impact – we match up to $2000 (or local currency equivalent) for financial donations and service.
• Up to 40 hours each year to use toward volunteer projects you love.
• Embracing parenthood with a minimum of 16 weeks of parental leave.

Security & Privacy Responsibilities:

Take ownership of protecting the confidentiality, integrity, and availability of organizational data and systems by following applicable privacy and security policies, standards, and procedures. Ensure that all individual contributions follow Elastic’s Secure Software Development Framework (SSDF). Proactively participate in mandatory role‑based training to ensure personal technical execution consistently aligns with the highest standards of data protection, data privacy, and system resilience.

Equal Opportunity and Accessibility Statement:

Elastic is an equal opportunity employer and is committed to creating an inclusive culture that celebrates different perspectives, experiences, and backgrounds. Qualified applicants will receive consideration for employment without regard to race, ethnicity, color, religion, sex, pregnancy, sexual orientation, gender perception or identity, national origin, age, marital status, protected veteran status, disability status, or any other basis protected by federal, state or local law, ordinance or regulation. We welcome individuals with disabilities and strive to create an accessible and inclusive experience for all individuals.