Senior Full-Stack Software Engineer, Applied AI

Circle

Senior Full-Stack Engineer developing innovative AI solutions leveraging LLMs for Circle's community platform. Collaborating on full-stack projects using Ruby on Rails and React with a global team.

Posted 7/9/2026full-timeRemote • 🇺🇸 United StatesSenior💰 $130,000 - $140,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in full-stack development with a focus on Ruby on Rails and React, alongside a strong background in building and optimizing AI features in production environments. Proven ability to design experiments and iterate quickly in a fast-paced, high-traffic application setting.

Highest-signal resume keywords

Full-Stack DevelopmentRuby On RailsReactJSAI Feature DevelopmentExperimentation Mindset

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

Ruby On RailsMySQLPostgresqlReactJSAI Feature DevelopmentA/B TestingPerformance OptimizationFull-Stack EngineeringHigh-Traffic ApplicationsExperiment Design

Soft Skills

Bias For ActionAdaptabilityCollaborationCommunication

Industry Keywords

AI InfrastructureCutting-Edge AI ResearchFast-Paced EnvironmentHigh StandardsFeature Design Process

Tech Stack

Tools & technologies

MySQLPostgresReactRubyRuby on Rails

About the role

Key responsibilities & impact

Ship full-stack AI projects end-to-end on a product built in Ruby on Rails backend and React frontend.
Design and run experiments (including A/B tests) to validate AI features.
Build and integrate components for AI infrastructure and optimize performance.
Help stay up-to-date with cutting-edge AI research, techniques, and tools.
Work closely with Circle's leaders and designers throughout the feature design process.
Foster a bias for action by prioritizing speed of iteration and maintaining high standards.

Requirements

What you’ll need

6+ years experience working as a full-stack engineer on high-traffic production applications.
Strong proficiency in Ruby on Rails, MySQL / Postgresql, ReactJS.
Hands-on experience building AI features in production.
Strong experimentation mindset.
A desire to work in a fast-paced environment with a certain level of ambiguity.
Strong alignment with company values.
Proficient in English (CEFR Level C2 / ILR Level 5).

Benefits

Comp & perks

35 days of paid time off each year.
Equity in the company with ongoing refresh grants.
U.S.-benchmarked compensation globally.
Incredible flexibility and autonomy.