Senior Software Engineer ($160k-$200k + Equity) at Numero

Join Numero as a Senior Backend Engineer to architect systems handling millions of daily requests and billions of records. You will scale our proprietary NumeroQL engine, integrate advanced AI agents into our product suite, and optimize high-volume payment processing. It’s a high-impact role building the infrastructure that powers consequential national campaigns., * Work on mission-critical systems where your code directly impacts thousands of campaigns and helps raise billions of dollars for important causes.

• Join a high-growth, YC-backed team with top-tier investors like 776 and Initialized Capital, operating at a scale few startups ever reach.
• Be at the forefront of AI-native development, utilizing agentic coding workflows and building LLM-powered features like Numero Agents on a proprietary Ruby stack.

What You Will Do

• Architect and scale backend systems using Ruby on Rails, Postgres, and OpenSearch to support billions of records and high-frequency election traffic.
• Develop and refine Numero Agents, a suite of AI-powered tools that allow clients to manage their platform using sophisticated natural language commands.
• Optimize complex payment processing and tandem fundraising features, ensuring high conversion and precise compliance reporting across Stripe and PayPal.

• Possesses 6+ years of experience building and scaling user-facing backend systems with a deep, instinctive understanding of production performance and cost.
• Demonstrates high proficiency in SQL and relational data modeling at scale, with experience managing bottlenecks and indexing in high-volume environments.
• Maintains a bias toward high-quality architectural patterns and is eager to push the frontier of AI-integrated engineering workflows using tools like Cursor.

Numero is a YC-backed fundraising platform that has helped political campaigns and nonprofits raise over $10B. Backed by investors like 776 and Initialized Capital, Numero provides an all-in-one CRM, payment processing, and communications toolkit that scales to serve thousands of campaigns during the most critical moments of national election cycles., Ok, I’ll go first. I’m Jack, an AI that gets to know you on a quick call, learning what you’re great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.

And I’m Jill, an AI Recruiter who talks to companies to understand who they’re looking to hire. Then I recruit from Jack’s network, making an introduction when I spot an excellent candidate.

How does this work?

• Jack’s an AI agent for job searching and career coaching. He works for you.
• Jill is the AI recruiter working for the company. She recruits from Jack’s network.
• If it’s a match and the company wants to meet you, they’ll make the intro. In the meantime, if you’d like, Jack will send you excellent alternatives.

We never post fake jobs

This isn’t a trick. This is an open role that Jill is currently recruiting for from Jack’s network.

Sometimes Jill’s clients ask her to anonymize their jobs when she advertises them, which means she can’t share all the details in the job description.

We appreciate this can make them look a bit suspect, but there isn’t much we can do about it.

Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we’re giving his services away for free.

About Jack & Jill