Top Senior Software Engineer Jobs in Portland, ME

As a Senior Software Engineer, you will build backend APIs for authentication and authorization, partner with leadership, and mentor other engineers while improving production quality.

The Senior Software Engineer will build full-stack solutions, design scalable features, mentor team members, and manage the development lifecycle.

Lead design and development of highly available payment processing, subscription billing, settlement, refunds, and reporting systems. Integrate with external payment processors and APMs, ensure automated build/test/deploy pipelines, debug production issues, optimize performance, decompose features for incremental releases, conduct design/code reviews, mentor junior engineers, and incorporate regulatory requirements (PCI‑DSS, PSD2/SCA, 3DS2).

Lead frontend architecture and technical direction for shared UI systems and design system. Build, maintain, and document reusable component libraries; collaborate with UX, product, and engineering. Champion accessibility, testing, performance, and design-to-code workflows. Mentor engineers, review contributions, and deliver major UI initiatives end-to-end while balancing technical debt and product needs.

Own and evolve high-scale backend and data-layer services. Design, build, test, and operate distributed backend services and APIs, improve reliability/latency/scale, take end-to-end ownership from design through production support, participate in on-call and incident response, and mentor peers while partnering with Product and SRE teams.

Lead full-stack development using React, Node and TypeScript. Design scalable architecture, write and review code, ensure performance, accessibility and security, mentor off-shore teams, participate in Agile ceremonies, support production (including weekends/off-hours), and collaborate with cross-functional teams to deliver business-critical applications.

Design, build, deploy, and operate backend services, APIs, integrations, and web applications. Own end-to-end features, improve CI/CD and observability, troubleshoot cross-service issues, participate on-call, and collaborate with product and leadership to deliver reliable production systems.

Design, build, and maintain scalable backend services and APIs for loan origination and servicing. Own features end-to-end, improve performance, reliability, CI/CD, mentor engineers, and translate complex financial requirements into reliable technical solutions.

Lead modernization of internal platform tooling to 12-factor apps, delivering full-stack services (Go/Python + React/Vue), instrumenting observability (Grafana/Prometheus/Loki), driving Kubernetes-native GitOps (ArgoCD/GitLab CI), mentoring developers, and automating infrastructure with Ansible/Terraform on private/bare-metal clouds.

Design, develop, and maintain complex, enterprise-scale software features and services across the OneStream CPM platform. Lead technical design, implement UI and APIs, ensure JSON/XML contract compatibility, improve performance and reliability, mentor engineers, participate in code reviews, and support CI/CD, testing, and production operations. Use AI-assisted development tools responsibly to accelerate development.

Own and evolve Roo's frontend platform: design system, shared UI architecture, developer tooling, and AI-assisted workflows. Lead migrations, React/React Native modernization, Expo adoption, and developer experience improvements. Partner with Product and Design to make components effortless to consume by engineers, designers, and AI agents, and remove platform friction to increase engineering velocity.

Design, build, and maintain secure microservices and data pipelines for analytics and alerting across a cloud-native identity platform. Implement IaC (Terraform) on Azure, develop CI/CD pipelines, optimize data flows and storage, ensure observability and security, conduct reviews, and mentor engineers.

Design, build, and own large-scale distributed backend systems in Go to process billions of events and petabytes of data. Lead architecture, reliability, observability, and performance efforts; improve service communication and data pipelines; debug production at scale; mentor engineers and share learnings publicly.

Design and build the planning and customer operations portal: geospatial routing and siting algorithms, automated permitting integrations, and deployment/customer dashboards. Implement backend services (TypeScript/Node), front-end features (React/TypeScript), and cloud infrastructure (Docker, Helm, Kubernetes, AWS) to accelerate hardware deployments and provide visibility into installations and fleet health.

Lead full‑stack modernization of a legacy .NET/SQL Server payment-integrity platform. Build modular Angular frontends and resilient .NET microservices, improve APIs, optimize database performance, embed security/privacy, use AI coding agents to accelerate refactors, and drive delivery with strong observability and testing practices.

Build and maintain C#/.NET Revit add-ins and Revit-integrated desktop apps that export model data to the Stratus platform. Solve Revit-specific challenges (version compatibility, threading, performance), integrate with backend services (Azure ServiceBus), manage installers/updates, triage customer bugs, write tests, and collaborate with product and customer teams. Use AI-assisted dev tooling as part of the development workflow.

Lead and mentor engineering teams to design and deliver scalable, high-performance systems. Define technical roadmaps, set code quality standards, drive architecture and technical debt resolution, collaborate with Product and Design, make technology decisions, lead hiring and interviews, and research new tools to solve complex problems while advocating for engineering priorities and timely feature delivery.

Design and deliver backend systems and APIs in Go, contribute full-stack features with React/TypeScript, lead complex technical projects, participate in on-call rotations, collaborate with product and design, and drive maintainable, scalable observability features.

Design, build, and scale backend systems and APIs for high-transaction consumer products. Collaborate with product, credit, compliance, support, and analytics teams. Contribute to code reviews, technical planning, security, and operational excellence. Mentor peers and promote engineering best practices.

The Staff Software Engineer will lead the design of the Integrations Platform's architecture, authoring framework, and integration strategies while coaching other engineers and ensuring high-quality integrations over multiple quarters.

The Senior Software Engineer will enhance Flow protocol's architecture, improve performance, and ensure reliability for decentralized applications and services.

Lead team in developing Enterprise B2B solutions, uphold quality standards, drive AI adoption, mentor engineers, guide architecture and legacy modernization efforts.

The Senior Software Engineer will design and implement backend solutions for a social casino platform, collaborate with team members on architecture, and review code, while ensuring the product meets user needs.

The Sr Software Engineer will lead IoT cloud software development, design data pipelines, manage cloud infrastructure, and ensure platform compliance while mentoring the development team.

As a Senior Software Engineer, you'll build and operate the ML platform, optimizing data operations, managing the feature store, and supporting ML initiatives while driving architectural roadmap decisions.