Senior Back-End Developer

Kots; Bengaluru; On-site; INR 2,500,000 - 4,000,000; Full time

Job summary

Kots in Bengaluru is seeking a hands-on Senior Back-End Developer who delivers production-grade server-side code using Python and relational databases. You will design and build the data layer and services behind our applications, running on AWS.

A builder mindset with deep SQL skills and clear ownership of code through tests, deployment, and production support is essential. This senior role requires strong Python (Flask/FastAPI) experience, proficiency with PostgreSQL/MySQL, and comfort with

Qualifications

• 4+ years of relevant, hands-on back-end development experience.
• Solid Python backend experience building REST APIs (Flask or FastAPI).
• SQL ability to write advanced queries and reason about execution.
• Schema design, indexing, and query optimization on real data volumes.
• API security with JWT/OAuth2 and OWASP risks.
• Testing — unit and integration tests with pytest.
• Experience with Git workflows, Docker, and CI/CD pipelines.

Responsibilities

• Design, build, and maintain Python (Flask/FastAPI) services and REST APIs.
• Write optimized SQL with multi-table joins, subqueries, and CTEs.
• Model relational schemas, design indexes, and tune slow queries.
• Plan safe schema migrations and handle live data changes.
• Implement authentication, authorization, and API security.
• Build background jobs, queues, and retry-safe tasks.
• Write unit/integration tests and ensure production readiness.
• Own services from deployment to monitoring and incident response.
• Review peers' code and mentor junior developers.

Skills

Python

SQL

REST APIs

Flask

FastAPI

AWS

Git

Testing (pytest)

CI/CD

Database design

Tools

Flask

FastAPI

PostgreSQL

MySQL

Docker

Celery

Job description

About the Role

We are looking for a hands-on Senior Back-End Developer who writes production-grade server-side code. You will design and build the services and data layer behind our applications using Python, with relational databases underneath. Our services run on AWS; cloud experience helps, but it is not a requirement.

This is a builder's role, not a coordinator's. You should be comfortable writing complex SQL by hand, designing REST APIs that other teams depend on, reasoning about performance and failure, and owning your code through testing, deployment and production support.

What You'll Do

• Design, build, and maintain Python (Flask/FastAPI) services and REST APIs consumed by our front ends and partners.
• Write and optimise advanced SQL multi-table joins, subqueries, CTEs, and window functions without leaning on an ORM to do the thinking for you.
• Model and evolve relational schemas, design indexes, and tune slow queries using EXPLAIN / EXPLAIN ANALYZE.
• Plan and run schema migrations safely against live data.
• Handle authentication, authorisation, and the security of the endpoints you expose.
• Build background jobs, queues, and scheduled work, and make them safe to retry.
• Write meaningful unit and integration tests for the code and modules you ship.
• Own your services through deployment, monitoring, and troubleshooting in production, and help improve build and release pipelines.
• Review peers' code, uphold quality standards, and mentor less experienced developers.

What We're Looking For

This is a senior back-end role we expect depth in Python and in relational databases, and the ability to run what you build.

• 4+ years of relevant, hands-on back-end development experience.
• Python solid backend experience building REST APIs (Flask or FastAPI), not just scripting.
• SQL ability to write advanced queries from scratch and reason about how they execute; PostgreSQL and/or MySQL in production.
• Schema design, indexing, and query optimisation on real data volumes.
• API security authentication and authorisation (JWT, OAuth2) and common OWASP risks.
• Testing — able to write proper unit and integration tests with pytest.
• Comfort with Git workflows, Docker, and CI/CD pipelines.

This Role Is Not a Fit If

• You work only in Java and have no Python experience or familiarity.
• You rely entirely on ORMs and cannot write raw SQL queries yourself.
• Your Python is scripting and automation only — you have never built and run a production service.
• You have never written tests for your own code.
• You are looking for a role that is mostly front-end work.

Nice to Have

• AWS — experience deploying and running workloads (e.g. ECS/Fargate, Lambda, RDS). Experience on GCP or Azure is also welcome.
• Async Python (asyncio) and an understanding of concurrency trade-offs.
• Queues and background processing — Celery, SQS, or Kafka.
• Caching strategies with Redis, and knowing when not to cache.
• Infrastructure as code (Terraform or AWS CDK).
• Observability — structured logging, metrics, tracing, and useful alerts.
• NoSQL stores (MongoDB, DynamoDB) alongside relational databases.
• Enough front-end familiarity (Angular or React) to debug an integration end to end

Please read the Job Description thoroughly before proceeding to apply.