Sr. Platform Engineer

Mosaic.tech; United States; On-site; USD 145,000 - 190,000; Full time

Job summary

Istari Digital is seeking a Senior Platform Engineer to own and evolve the Core Platform architecture, including backend services, SDKs, and AI-enabled capabilities. You will design scalable APIs and event-driven systems, and lead architectural decisions across the team.

The role emphasizes hands-on leadership, reliability, observability, and secure, cost-aware production deployments. You will mentor engineers and drive best practices across design, development, testing, and operations.

Qualifications

• 5+ years of professional software engineering experience.
• Experience building scalable, reliable, distributed systems with AI/ML capabilities.
• REST API design and implementation expertise.
• Experience designing event-driven architectures.
• Strong leadership and collaboration across teams.

Responsibilities

• Own the end-to-end architecture of the Core Platform, including backend services, SDKs, AI-enabled components, and related infrastructure.
• Design and implement scalable APIs, event-driven systems, distributed services, and AI-integrated capabilities.
• Architect systems that incorporate AI models with focus on observability, latency, cost, and failure handling.
• Lead API design and implementation for usability, performance, and maintainability.
• Architect and evolve microservices using domain-driven design.
• Build platform abstractions for AI-driven workflows and agent-based capabilities.
• Partner with Product, Infra, and Customer Success teams to deliver seamless integrations.
• Provide technical leadership and architectural guidance to engineers.
• Establish and elevate engineering best practices across design, development, testing, and operations.

Skills

Distributed systems design

REST API design

Python

Go

TypeScript

Cross-functional leadership

Mentorship

Event-driven architecture

AI/ML integration

Architectural judgment

Tools

Python

Go

TypeScript

Job description

We are seeking a Senior Platform Engineer to join our Core Platform team. In this role, you will own and evolve the end-to-end architecture of the Core Platform, including backend services, SDKs, AI-enabled capabilities, and supporting infrastructure.

You will design and operate scalable APIs, event-driven systems, distributed services, and AI-integrated workflows, ensuring high standards for reliability, performance, observability, and security. This role requires strong architectural judgment, hands‑on technical leadership, and the ability to collaborate cross‑functionally to deliver extensible platform capabilities that support both traditional integrations and AI‑driven use cases.

You will help set technical direction, mentor engineers, and drive engineering best practices across the team.

Core Responsibilities

• Own the end-to-end architecture of the Core Platform, including backend services, SDKs, AI-enabled components, and related infrastructure.
• Design and implement scalable APIs, event-driven systems, distributed services, and AI-integrated capabilities (including AI/ML and MCP integrations).
• Architect systems that reliably incorporate AI models into production environments, with strong attention to observability, latency, cost management, and failure handling.
• Lead API design and implementation with a focus on usability, performance, and long-term maintainability.
• Architect and evolve microservices using domain-driven design principles.
• Build platform abstractions and primitives that enable AI‑driven workflows and agent‑based capabilities.
• Partner closely with Product, Infra, and Customer Success teams to deliver seamless, customer‑centric integration capabilities.
• Provide technical leadership, mentorship, and architectural guidance to engineers.
• Establish and elevate engineering best practices across design, development, testing, and operations.

Required Qualifications

• 5+ years of professional software engineering experience.
• Proven experience building scalable, reliable, and secure distributed systems, including systems that integrate AI/ML capabilities.
• Experience integrating AI-powered features into production systems, with an understanding of performance, reliability, and governance considerations.
• Deep expertise in REST API design and implementation.
• Experience designing and operating event-driven architectures.
• Strong coding skills across multiple layers of the stack (backend services, SDKs, developer tooling, and AI-integrated systems).
• Strong understanding of microservices architecture and domain-driven design.
• Strong proficiency in Python (object-oriented and functional programming).
• Experience with Golang and TypeScript desired.
• Track record of technical leadership, mentorship, and cross-functional collaboration.
• Excellent communication skills with the ability to influence at both technical and strategic levels.
• Must be a US citizen living within the United States.

About Istari Digital

Istari is a digital engineering software company building open, scalable infrastructure for engineering data. Our platform lets customers simply and securely integrate engineering models across disciplines, organizations, and security levels - whether they're designing prototypes, performing virtual testing, or training AI and autonomy for complex systems.

Focus is rewarded. Finish is remembered.

Facts are friendly. Even when they are not fun.

Fellowship is fundamental. Make others successful.

145000 - 190000 USD a year

The anticipated compensation range for this position may vary based on experience, skills, qualifications, location, and business needs. In addition to base salary, this role may be eligible for bonuses, equity, and a comprehensive benefits package.