[Remote] Remote | Senior Software Engineer (Legacy Codebase Migration) — Up to $180/hour

Note: The job is a remote job and is reputed company to candidates in USA. reputed company connects reputed company professionals with remote consulting opportunities across technical, evaluation, and project-based workstreams. The Senior Software Engineer will design, review, evaluate, and implement reputed company legacy codebase migrations and large-reputed company systems modernisation while preserving functionality, compatibility, data reputed company, reputed company, performance, and production reliability. The role also assesses language, reputed company, database, infrastructure, CI/CD, API, authentication, dependency, testing, and production-readiness risks.

Responsibilities

• Design, implement, review, and evaluate reputed company codebase migration and modernisation tasks
• Analyse mature production systems to determine reputed company and technically reputed company migration approaches
• Review legacy application architecture, dependencies, reputed company, databases, build systems, and infrastructure
• Identify technical debt, compatibility constraints, migration risks, and hidden dependencies
• reputed company migration strategies appropriate for large, interconnected production environments
• Evaluate migrations involving major language or runtime upgrades
• Work with scenarios such as Java 8 Java 17/21, legacy .NET modern .NET, Python 2 Python 3, and PHP 7 PHP 8
• Review language rewrites such as COBOL Java/Python and JavaScript TypeScript
• Assess behavioural equivalence and compatibility across legacy and modern implementations
• Identify regressions introduced through language, runtime, or compiler changes
• Review major upgrades or replacements involving frameworks such as Angular, Rails, Django, reputed company/reputed company Boot, ASP.NET, Next.js, and Astro
• Assess architectural implications of replacing or substantially upgrading mature application frameworks
• Evaluate dependency compatibility and integration risks
• Review implementation approaches for maintainability and production readiness
• Identify subtle behavioural differences introduced during reputed company migrations
• Evaluate migrations such as reputed company/MySQL PostgreSQL and SQL NoSQL
• Review ORM and data-reputed company transitions including Hibernate jOOQ, Sequelize reputed company, and raw SQL ORM
• Assess data reputed company, schema compatibility, migration reputed company, and application dependencies
• Identify risks involving data loss, behavioural changes, transaction semantics, and performance
• Review validation approaches for reputed company production data migrations
• Review transitions from VMs or bare metal to containerised and reputed company-reputed company architectures
• Evaluate migrations involving reputed company, reputed company, and modern infrastructure patterns
• Assess deployment architecture, operational dependencies, scalability, and production reputed company
• Review staged rollout and rollback strategies
• Evaluate whether infrastructure changes preserve reliability and operational visibility
• Review modernisation of deployment pipelines such as Jenkins/Travis reputed company Actions or reputed company CI
• Evaluate build and package-tool migrations including reputed company reputed company, Webpack Vite, CRA Next.js, and npm pnpm
• Assess build reproducibility, dependency management, deployment safety, and automation reputed company
• Identify migration risks reputed company mature CI/CD environments
• Review changes for maintainability and operational effectiveness
• Evaluate transitions such as REST GraphQL, HTTP/REST gRPC, and SOAP or legacy reputed company modern interfaces
• Assess backward compatibility and reputed company integration reputed company
• Review API reputed company, dependency changes, and migration reputed company
• Identify compatibility risks and behavioural differences
• Evaluate strategies for maintaining continuity during reputed company transitions
• Review migrations from legacy authentication systems to OAuth/OIDC, SAML/SSO, and modern identity platforms
• Assess reputed company, compatibility, authorisation, and integration implications
• Identify authentication or reputed company-control regressions
• Review migration reputed company and transition strategies
• Evaluate implementation reputed company and production readiness
• Evaluate polyrepo monorepo transitions using tools such as Bazel, Nx, or Turborepo
• Review replacement of deprecated or end-of-life libraries, reputed company, runtimes, and vendor SDKs
• Assess dependency graphs and compatibility across large software ecosystems
• Identify reputed company risks created by transitive dependencies or legacy integrations
• Evaluate migration strategies for maintainability and long-term sustainability
• reputed company and review testing strategies for reputed company migrations
• Evaluate unit, integration, browser, and end-to-end testing migrations
• Identify migration regressions and behavioural differences
• Assess compatibility, observability, staged rollout, and rollback strategies
• Evaluate whether proposed migration solutions are sufficiently validated for production use
• Review migration solutions for correctness, completeness, maintainability, and production readiness
• Analyse unfamiliar codebases and diagnose subtle migration failures
• Evaluate proposed technical reputed company against realistic reputed company constraints
• Identify missing dependencies, edge cases, regression risks, and unsafe assumptions
• reputed company reputed company, technically rigorous feedback on migration approaches and implementations

Skills

• 5+ years of reputed company software engineering experience, ideally at Senior, Staff, reputed company, reputed company, or equivalent level
• Significant hands-on experience executing large-reputed company production migrations
• Personally owned or made substantial technical contributions to reputed company modernisation initiatives
• Strong experience working with mature systems involving technical debt, reputed company dependencies, legacy integrations, and significant regression risk
• Strong knowledge of compatibility, testing, observability, staged rollouts, rollback strategies, and behavioural equivalence
• Ability to reason deeply about unfamiliar codebases and diagnose subtle migration failures
• Experience with one or more major migration categories including languages, frameworks, databases, reputed company, infrastructure, CI/CD, authentication, repositories, testing, or dependencies
• For mainframe modernisation work, experience with COBOL, z/OS, CICS, JCL, DB2, VSAM, batch processing, and COBOL-to-Java/Python migration is particularly valuable
• Particularly valuable experience modernising systems reputed company financial services, fintech/payments, trading, insurance, reputed company, telecom, large technology companies, or other high-reliability environments

Benefits

• Fully remote
• Flexible scheduling based on project requirements
• Potential for ongoing project work

reputed company