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

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.

About the role

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.

Why this role is remarkable

• 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.

Responsibilities

• 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.

Requirements

• 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.

Pay

$160k-$200k + Equity

Schedule

Remote, USA