Application Guide

How to Apply for Staff Software Engineer / Tech Lead

at Safi

🏢 About Safi

Safi is tackling the global waste crisis by using AI to transform recycling efficiency. Their platform combines computer vision with a global marketplace, enabling recycling plants to improve quality and access better markets. This is a rare opportunity to apply cutting-edge AI to a tangible, high-impact environmental problem.

About This Role

As Staff Engineer / Tech Lead, you'll own the technical architecture of Safi's core systems, from backend to frontend, and deploy AI solutions directly in industrial recycling plants. You'll work end-to-end: identifying problems, shipping features, and collaborating with customers and ML engineers to turn model outputs into usable tools for plant operators. This role balances deep technical leadership with hands-on, on-site impact.

💡 A Day in the Life

Your day might start with a standup with the remote team, then dive into coding on a new feature for the plant operator dashboard. After lunch, you could hop on a call with a customer to understand a pain point, then spend the afternoon designing an architecture for integrating a new sensor feed. Once a month, you'd travel to a recycling plant to see the system in action and iterate based on real-world feedback.

🚀 Application Tools

Generate Cover Letter

AI-powered, tailored for Safi

Interview Prep

Practice questions for this role

🎯 Who Safi Is Looking For

  • You have 5+ years shipping software in fast-paced environments, with a strong focus on monitoring and testing to ensure reliability in production.
  • You're deeply experienced with Python, Django, React/React Native, PostgreSQL, and Google Cloud, and can make architectural trade-offs confidently.
  • You're comfortable with autonomy and leading user-facing projects from conception to deployment, including traveling to customer sites or London HQ monthly.
  • You thrive in a startup environment where you can wear multiple hats and are excited by the challenge of deploying AI in industrial settings.

📝 Tips for Applying to Safi

1

Highlight specific projects where you led end-to-end delivery of a user-facing feature, including architectural decisions and trade-offs made.

2

Showcase your experience with Django and React/React Native in production, especially any work involving real-time data or complex state management.

3

Demonstrate your comfort with autonomy by describing a time you owned a project from problem identification to shipped feature with minimal oversight.

4

Mention any experience working with or deploying ML models in production, even if not directly responsible for the model itself.

5

Explicitly state your willingness and ability to travel monthly to customer sites or London HQ, and that your timezone is within +/-2 hours of London.

✉️ What to Emphasize in Your Cover Letter

['Your passion for using technology to solve environmental problems, specifically waste and recycling.', 'Your track record of leading technical projects end-to-end in fast-moving startups or similar environments.', "Your ability to balance speed with reliability, and specific examples of monitoring and testing practices you've implemented.", 'Your comfort with ambiguity and autonomy, and your willingness to travel to industrial sites.']

Generate Cover Letter →

🔍 Research Before Applying

To stand out, make sure you've researched:

  • → Read Safi's blog or any press releases to understand their current AI capabilities and how they measure recycling quality.
  • → Look into the technical challenges of deploying computer vision in industrial environments (lighting, dust, camera angles).
  • → Understand the recycling industry basics: what materials are sorted, how quality is assessed, and the current market dynamics.
  • → Check out Safi's team page on LinkedIn to see the backgrounds of existing engineers and the CTO.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Walk us through a recent project where you were the tech lead: how did you make architectural decisions and handle trade-offs?
2 How would you design a system to ingest real-time video from recycling plants, process it with an AI model, and display actionable insights to operators?
3 Describe a time you had to ship a feature quickly while maintaining high quality. What monitoring and testing did you put in place?
4 How do you approach collaborating with non-technical stakeholders (e.g., plant operators) to understand their needs and iterate on a product?
5 Given Safi's stack (Python, Django, React, PostgreSQL, GCP), how would you optimize a slow database query that's critical to the user experience?
Practice Interview Questions →

⚠️ Common Mistakes to Avoid

  • Don't focus only on backend or frontend; this role requires full-stack thinking and willingness to touch both.
  • Avoid vague statements about 'passion for environment' without concrete examples of how you've applied tech to real-world problems.
  • Don't downplay the travel requirement; be upfront about your availability and willingness to go on-site.

📅 Application Timeline

This position is open until filled. However, we recommend applying as soon as possible as roles at mission-driven organizations tend to fill quickly.

Typical hiring timeline:

1

Application Review

1-2 weeks

2

Initial Screening

Phone call or written assessment

3

Interviews

1-2 rounds, usually virtual

✓

Offer

Congratulations!

Ready to Apply?

Good luck with your application to Safi!

← Back to Job Listing Apply Now →