Senior Engineer (Backend)

About the Role
As a Senior Backend Engineer at Sage, you will be responsible for building, enhancing and maintaining a high-quality SaaS solution that exceeds customer and business partner expectations. You will proactively share your own knowledge for specific technical solutions and business processes in your area of responsibility. We are looking for someone with 7+ years of professional experience in backend engineering. Proficiency in English, written and verbal, is required.
We value humility and collaboration. We are looking for people who can work as part of a team, not in silos. We expect engineers to take ownership beyond just writing code, including tests, documentation, and long-term code quality.

Location: Bangalore, India. This is a hybrid role, three days per week in the office.

Required Skills
Core languages & runtime

• Strong TypeScript (strict mode) and Node.js (v24+) for production services.
• Solid computer-science fundamentals: data structures, algorithms, concurrency, async I/O.

Backend frameworks & APIs

• REST API design with Fastify (or Express/NestJS/Koa with willingness to learn Fastify).
• JSON Schema contract design and validation (AJV or equivalent); OpenAPI/Swagger.
• Understanding of API versioning, idempotency, pagination, and error-handling patterns.

Data & persistence

• Relational databases MySQL and/or PostgreSQL: schema design, indexing, query tuning.
• Comfort with JSON-document modeling in a relational store and query compilation to SQL.
• SQL query builders (Knex or similar); parameterized queries and SQL-injection prevention.
• Caching with Redis.

Distributed systems & messaging

• Event-driven / message-queue systems (AWS SQS, or Kafka/RabbitMQ/SNS equivalents): producer/consumer patterns, dead-letter queues, retries/backoff, and idempotency.
• Designing for at-least-once delivery and eventual consistency.

Cloud & platform

• AWS services (SQS, EFS, S3, IAM, ECR) in a production context.
• Containerization with Docker; familiarity with Kubernetes deployments.

Security

• OAuth2 / OIDC / JWT validation (RS256, JWKS), token propagation, and multi-issuer auth.
• Secure coding against the OWASP Top 10; multi-tenant isolation and row-level security.

Testing & quality

• Unit, integration, and contract testing (Vitest/Jest or equivalent); test-driven mindset.
• Linters/formatters (Biome, ESLint/Prettier) and CI discipline.

Tooling & workflow

• Git and pull-request workflows; monorepo experience (Nx) a plus.
• CI/CD (GitHub Actions or similar).

AI Tooling

• Productive use of AI-assisted developer tooling (e.g. GitHub Copilot, Claude Code, Cursor) to accelerate day-to-day backend development.
• Integrating LLM / generative-AI capabilities into backend services (e.g. OpenAI, Anthropic, AWS Bedrock) via SDKs, streaming responses, and prompt/response validation.
• Familiarity with retrieval-augmented generation (RAG): embeddings, vector stores/search, and context assembly pipelines.

Nice to Have

• MongoDB-like query languages or building a query compiler/DSL.
• KEDA / autoscaling on queue depth; Istio service mesh; Argo Rollouts canary deploys.
• GitOps (ArgoCD) and schema-driven DB migrations (Atlas or Liquibase/Flyway).
• Observability stacks: New Relic APM, Sumo Logic, Prometheus, Pino logging.
• Domain knowledge in finance, ERP, FP&A, or accounting systems.
• Experience building AI/ML-powered backend features such as forecasting, anomaly detection, or natural-language querying over financial data.

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