Principal Engineer

Principal Engineer

Location: Remote / Islamabad
Type: Full-time

About Fastn

Fastn is on a mission to revolutionize how SaaS companies connect with their customers' environments. Powered by AI, we provide an embedded integration infrastructure that enables SaaS businesses to build, scale, and manage their integration ecosystem effortlessly.

With Fastn, companies can launch strategic integrations, create their own app marketplace, and unlock new revenue streams by offering seamless connectivity with the tools their customers already use. But our platform is more than just integrations its about accelerating market penetration, driving partner-sourced revenue, and delivering smarter, more valuable customer experiences.

If youre passionate about architecting large-scale distributed systems, leading high-impact engineering teams, and pushing the boundaries of SaaS connectivity, Fastn is the place to be.

What Youll Do

As a Principal Engineer, you will play a foundational role in defining and executing Fastns technical vision. You will be responsible for architecting, optimizing, and scaling our AI-powered integration infrastructure to handle millions of transactions per second with sub-millisecond latency. Youll work closely with engineering leaders, product teams, and executives to drive technical strategy, innovation, and engineering excellence.

This role is ideal for someone who is not just a world-class engineer but also a strategic thinker, mentor, and influencer who thrives in a fast-moving, high-growth startup environment.

Your Responsibilities

• Technical Strategy & Architecture: Define and lead the architecture, scalability, and reliability roadmap for Fastns core platform.
• High-Scale Systems: Design and optimize low-latency, high-throughput distributed systems capable of handling millions of transactions per second/minute.
• AI-Powered Integrations: Leverage AI/ML to enhance automation, data mapping, and intelligent API connectivity.
• Performance Optimization: Drive initiatives to ensure sub-millisecond API response times and seamless scaling.
• Security & Compliance: Implement world-class security best practices across API authentication, data privacy, and regulatory compliance (SOC 2, GDPR, etc.).
• Technical Leadership & Mentorship: Lead and mentor engineers, fostering a culture of technical excellence, knowledge-sharing, and continuous improvement.
• Cross-Functional Collaboration: Partner with product, engineering, and customer success teams to align business goals with technical execution.
• Hands-On Engineering: While youll shape the big-picture strategy, you should also be comfortable writing high-impact code and conducting deep technical reviews.

What Were Looking For

Were seeking an exceptional technical leader who thrives in solving high-scale distributed systems challenges while also guiding and mentoring top-tier engineers. If youre obsessed with performance, scalability, and building world-class engineering teams, this role is for you.

Must-Have Skills & Experience

• 10+ years of hands-on software engineering experience, with at least 3+ years in a Principal/Architect role in high-scale SaaS, API, or distributed systems.
• Proven track record of designing, building, and scaling distributed systems handling millions of transactions per second/minute with sub-millisecond latency.
• Deep expertise in backend development using Java, Python, or (Fastns stack is flexible).
• Strong understanding of high-performance, low-latency computing, caching strategies, and database optimization.
• Experience working with cloud platforms (AWS, GCP, Azure) and serverless architectures.
• Knowledge of event-driven architectures, message queues (Kafka, RabbitMQ, etc.), and real-time data processing pipelines.
• Expertise in API security, authentication (OAuth, JWT, OpenID), and compliance standards (SOC 2, GDPR, etc.).
• Experience in leading and mentoring engineering teams, fostering a high-performance, collaborative culture.

Nice-to-Have Skills

• Experience with iPaaS (Integration Platform as a Service) tools like Mulesoft, Workato, or
• Hands-on experience with AI/ML-driven automation in integrations and API intelligence.
• Previous work in developer tooling, B2B SaaS integrations, or API marketplaces.

Why Join Fastn?
Shape the Future of SaaS Connectivity Build and lead a game-changing integration infrastructure.

• Work on Cutting-Edge AI & API Technologies Be at the forefront of AI-powered SaaS integrations.
• High-Impact, High-Growth Environment Your contributions will directly define Fastns trajectory.
• Strong Engineering Culture Collaborate with world-class engineers solving highly complex challenges.
• Competitive Compensation Market-leading salary, meaningful equity, and a flexible work environment.

Join Us in Building the Future of SaaS Connectivity

If youre excited to architect high-scale distributed systems, lead engineering teams, and push the boundaries of performance and scalability, wed love to hear from you.

Apply now and help shape the future of SaaS integrations

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