Senior Kotlin/Spring Boot Engineer at Phoenix, AZ (Onsite)

Position: Senior Kotlin/Spring Boot Engineer

Location: Phoenix, AZ (Onsite)

Duration: Long term C2C

Skills: Kotlin Engineer, Kotlin, Spring boot, Temporal

Job Description:

We’re hiring a senior Kotlin/Spring Boot contractor to help own the execution backbone of a no-code workflow platform. This is not a simple CRUD service. The Orchestrator runtime is a multi-module system that receives workflow execution requests, persists durable state with Temporal, coordinates graph execution, integrates HTTP, agent, LLM, and human-review nodes, and safely executes increasingly AI-generated workflow graphs. You’ll join the squad responsible for the runtime layer that everything else depends on.

Responsibilities:

·        Design and harden the Kotlin/Spring Boot runtime that executes workflow graphs reliably in production.

·        Implement and improve Temporal.io workflows, activities, signals, queries, retries, and recovery paths.

·        Strengthen contract-first APIs and shared contracts.

·        Own failure-mode thinking across distributed execution retries, idempotency, partial failure, replay safety, pause/resume, and graceful degradation.

·        Work across node types, including HTTP, agentic tool-calling, LLM, and human-in-the-loop review nodes.

·        Improve integration coverage using Test containers and layered Docker Compose profiles.

·        Collaborate closely with Composer and AI/KB teams on execution semantics and runtime behavior.

·        Write clear operational documentation and runbooks for a reliability-critical service.

Qualifications:

·        Strong production Kotlin backend experience.

·        Strong Spring Boot experience in distributed systems or platform services.

·        Hands-on Temporal experience in production.

·        Strong understanding of workflow durability, retries, idempotency, and recovery design.

·        Experience with multi-module Gradle codebases and contract-first API design.

·        Experience with JPA/Hibernate and PostgreSQL.

·        Experience with Docker Compose/Test containers integration testing.

·        Comfort debugging multi-service systems with mixed Kotlin and Python components.

·        Experience with observability tools like micrometer

·        Experience with contract first development

Strong Pluses:

·        Experience with DAG/workflow/orchestration engines.

·        Experience with AI/LLM/agent runtimes or other non-deterministic execution systems.

·        Familiarity with FastAPI-based workers and cross-language integration.

·        Experience with auth/token provider abstractions, OAuth2/JWT, or cached token acquisition.

·        Experience writing operational docs, runbooks, and reliability guidance.