Senior Full Stack Developer

About OpenTrain

OpenTrain AI is the hiring and contracting organization for this role and the #1 platform for finding and building careers in AI training and data labeling. OpenTrain helps people discover cutting-edge projects, build their profiles, and apply in minutes through a free account.

About AI Training and Code Evaluation

AI training is the human side of building artificial intelligence. Contributors help modern AI systems improve by preparing examples, reviewing outputs, and evaluating whether generated content is accurate, useful, secure, and technically sound.

In this project, your software engineering expertise will help assess AI-generated solutions against real-world engineering standards. This is flexible, remote-oriented work in a fast-growing technology field, where human judgment directly shapes how AI systems behave.

The Role

OpenTrain is seeking a Senior Full Stack Developer for a contractor engagement focused on full-stack software development and AI code evaluation. You will work across front-end and back-end systems, investigate complex technical issues, and review AI-generated solutions for quality and production readiness.

• Contractor, part-time engagement
• Approximately 15 hours per week, with an expected commitment of under 20 hours
• Flexible schedule with hours and days chosen by you, including weekends when there is activity
• Expected project duration of 3 to 6 months
• Pay rate of $50-$100 per hour

What You'll Do

You will contribute across complete application systems, from browser experiences and front-end applications through APIs, services, databases, external integrations, and deployment environments. The work requires careful investigation of unfamiliar repositories and strong judgment when assessing technical solutions.

• Develop, modify, and debug front-end and back-end application components.
• Implement user-facing features, services, APIs, and supporting data models.
• Trace requests and data across browsers, front-end applications, APIs, services, databases, and external integrations.
• Understand existing application architecture while working in unfamiliar repositories.
• Diagnose failures involving application state, API contracts, authentication, persistence, networking, and deployment.
• Evaluate and improve code written in multiple programming languages.
• Review AI-generated solutions for correctness, completeness, performance, security, and maintainability.

Required Qualifications

This is an expert-level opportunity for an experienced full-stack software engineer. Candidates should bring strong professional experience developing production applications and be comfortable understanding and contributing to the architecture of complete software systems.

• Strong professional experience developing production full-stack applications.
• Meaningful hands-on experience with both front-end and back-end engineering.
• Production experience with multiple programming languages.
• Strong knowledge of browser applications, APIs, application state, databases, and service integration.
• Experience understanding and contributing to complete software system architecture.
• Ability to work effectively in unfamiliar codebases.
• Strong debugging and technical problem-solving skills.
• Fluent English proficiency.

Eligibility and Application Details

Candidates must be based in the United Kingdom, United States, Canada, Germany, Australia, Ireland, or New Zealand. The engagement is designed for experienced contributors seeking flexible, part-time work alongside other commitments.

• Eligible locations: United Kingdom, United States, Canada, Germany, Australia, Ireland, and New Zealand
• Experience level: Expert
• Time requirement: Less than 20 hours per week
• Payment type: Hourly contractor compensation
• Rate range: $50-$100 per hour

How to Apply Through OpenTrain

Create a free OpenTrain account to build your profile and apply in minutes. OpenTrain brings together opportunities where skilled contributors help develop and evaluate the AI systems shaping the future of technology.