Software Engineer in Markham

Langflow is one of the most exciting and rapidly growing parts of our company. Langflow powers our open-source community, cloud offerings, and upcoming integrations with major platforms like NVidia R2X and IBM WatsonX. Our engineering team is scaling to meet demand, and we’re creating a new Core Systems group focused on building the execution engine that powers Langflow applications at scale.

Your role and responsibilities

We are looking for a Core Systems Software Engineer to join the new Langflow Runtime team. Your mission will be to help build a highly efficient, reliable, and scalable execution environment for Langflow applications — capable of serving thousands of concurrent users with low latency and high resiliency. This is a deep technical systems role — not a frontend or typical backend “web app” position. You will work on the foundation of Langflow’s production infrastructure, ensuring we can deliver a world-class runtime experience both in the cloud and on-premises. You will be joining a collaborative team of experienced engineers, working closely with other Langflow groups building the open-source platform, the cloud-hosted product (Astra integration), and the IBM Watson integration.

What you will do:

• Design, build, and optimize a new runtime execution engine for Langflow applications.
• Profile and optimize system performance (e.g., memory management, concurrency, throughput).
• Refactor parts of the existing Python-based runtime to improve reliability while building a next-generation architecture.
• Collaborate closely with the open-source and cloud product teams to ensure seamless integration.
• Participate in architecture discussions, design reviews, and planning sessions.
• Contribute to a strong engineering culture with code reviews, testing, and best practices.
• Mentor and support fellow engineers on system design and runtime development best practices.

Required education

• Bachelor’s Degree

Preferred education

• Master’s Degree

Required technical and professional expertise

Your Experience should include (Required experience):

• Software engineering experience with a focus on core systems, distributed systems, or runtime environments.
• Strong professional experience with Python.
• Experience building scalable, concurrent server-side systems — not just API endpoints.
• Familiarity with performance profiling and optimization (memory, CPU, network bottlenecks).
• Background with at least one lower-level systems language such as Go, Rust, or Java.
• Practical experience working on cloud-based services or other large-scale production environments.
• Ability to reason about system behavior under load, failure conditions, and scaling pressure.
• Experience with distributed systems patterns (e.g., actors, queues, caching, retries).
• Excellent communication skills and a collaborative, team-oriented mindset.

Preferred technical and professional experience

Nice to Have (Preferred experience):

• Experience with open-source projects like Ray, Dagster, Dask or FastAPI.
• Previous contributions to cloud runtime infrastructure, ML ops infrastructure, or serverless runtimes.
• Interest in future leadership opportunities (e.g., tech lead roles as the team grows).

Must have the ability to work in Canada without sponsorship. This role will involve working with technology that is covered by Export Regulations sanctions. If you are a Foreign National from any of the following US sanctioned countries (Cuba, Iran, North Korea, Syria, and the Crimea, Luhansk, Donetsk, Kherson, and Zaporizhia regions of Ukraine) on a work permit, you are not eligible for employment in this position.