Part-Time Contract Developer (Mid–Senior)

Part-Time Contract Developer (Mid–Senior)Lynx — environmental, health, and safety platform20 hours per week · Contract · $75–$120/hour · Remote (US time zones with overlap with Denver)Lynx is a multi-tenant environmental, health, and safety platform used by industrial operators to manage incidents and events, environmental monitoring, commitments, inspections, and compliance. The product includes a React web application, a .NET API, and an Expo mobile client, backed by PostgreSQL and AWS.We are based in Denver, Colorado, and welcome remote candidates whose schedules overlap with the Mountain Time workday. This contract position is 20 hours per week at $75–$120 per hour, depending on experience.You will design and deliver changes across the web application and API, with occasional work on the mobile client. Our customers work with large datasets, so pagination, appropriately scoped queries, and background jobs are standard parts of development. You will manage a focused queue of work, taking features from initial requirements through implementation and testing.Typical work includes:

• Developing features and resolving issues in the React web application (Vite, React 18, TypeScript and JavaScript, MUI, Redux Toolkit) and the .NET 10 API (ASP.NET Core, Entity Framework Core, PostgreSQL).
• Contributing occasional updates to the Expo / React Native application.
• Implementing data model changes and EF Core migrations, with review before they are applied.
• Building server-side grids, filters, and exports that maintain accuracy across tens or hundreds of thousands of rows.
• Queuing background tasks, including imports, exports, and recalculations, outside the request thread.
• Writing and running tests for changed functionality and validating the user workflow before considering a change complete.
• Translating customer or product requests into a clear scope, including user needs, edge cases, and completion criteria.Required
• Several years of experience delivering production software at a mid or senior level, with the ability to independently take a feature from initial requirements to a reviewed change.
• Strong experience in React or .NET, with sufficient knowledge of the other to contribute across the stack. You should be productive in both within the first few months.
• Experience working with relational data, including PostgreSQL or a similar database, Entity Framework or another ORM, and queries that perform efficiently on large tables.
• A commitment to quality assurance as part of development, including writing automated tests that provide meaningful coverage and validating changed workflows across empty states, errors, and permission differences.
• Clear written communication. With a 20-hour workweek, progress, questions, and tradeoffs should be documented clearly so the team can stay aligned without requiring a meeting.
• Experience with Git and code review, with a consistent practice of making small, reviewable changes.
• Eligibility to contract in the US, with working hours that overlap with Denver (Mountain Time).Preferred
• Business analysis experience, including reviewing workflows such as inspections, monitoring results, or compliance rules, writing acceptance criteria, and identifying gaps before development. Experience writing user stories, comparing current and proposed processes, or working directly with operations or compliance users is also valuable.
• Domain experience in EHS, ESG, environmental monitoring, mining, energy, or other regulated operations.
• Experience with React Native / Expo, Auth0, AWS (S3, background workers, Elastic Beanstalk or similar), Redis, or geospatial data (Mapbox, PostGIS).
• Experience with bilingual English and Spanish product copy or maintaining consistency across localization files.
• Familiarity with MUI X Data Grid or building filterable administrative grids with server-side pagination.Stack
• Web: React 18, Vite, TypeScript and JavaScript, MUI v7, Redux Toolkit, React Router, Yarn, Node 22.
• Mobile: Expo 54, React Native, TypeScript.
• API: .NET 10, ASP.NET Core, Entity Framework Core, AutoMapper.
• Data: PostgreSQL (Npgsql, NetTopologySuite), Redis.
• Platform: Auth0, AWS (S3, logging, background workers), English and Spanish localization.Engagement
• Contract, 1099 or corp-to-corp.
• 20 hours per week, ongoing.
• $75–$120 per hour, depending on experience. Remote, with working hours that overlap with the Denver workday.