Senior Python Developer/ Engineer

Cognizant; London Colney; On-site; GBP 70,000 - 90,000; Full time

Job summary

Cognizant is seeking a skilled backend engineer to develop secure, scalable features for its Digital Onboarding Service. You will work in a serverless and containerized AWS environment, building RESTful APIs and microservices with Python frameworks such as FastAPI or Flask.

You will collaborate with cross-functional teams to translate business requirements into robust technical solutions, implement integration patterns, and contribute to code quality, testing, and DevOps practices in an Agile

Qualifications

• Professional software engineer with backend focus.
• Strong experience with Python and modern backend frameworks.
• Extensive API, microservices, and backend services development.
• Hands-on AWS cloud services and serverless architecture expertise.
• Experience deploying containerized apps with Docker and ECS/Fargate.
• Knowledge of secure API design and authentication methods.
• Familiarity with relational and NoSQL databases.

Responsibilities

• Develop high-quality backend features for the Digital Onboarding Service using Python.
• Design, develop, and maintain RESTful APIs and microservices.
• Build cloud-native solutions on AWS with serverless and containerized patterns.
• Collaborate with engineers, architects, and product teams on technical designs.
• Integrate with internal and external systems via REST/webhooks/APIs.
• Apply design patterns and best practices for maintainable code.
• Enhance CI/CD pipelines and support deployment processes with DevOps.
• Document technical work and share knowledge within the team.
• Contribute to testing, performance tuning, and reliability improvements.

Skills

Python

FastAPI/Flask

RESTful APIs

AWS cloud

Docker

Serverless

Agile/Scrum

Security (OAuth2/JWT/OpenID)

SQL/NoSQL databases

Infrastructure as Code

OpenAPI/Swagger

CI/CD

Tools

Docker

AWS ECS/Fargate

Terraform

OpenAPI/Swagger

GitHub Actions

Job description

Responsibilities

• Develop high quality, secure, and maintainable features for the client Digital Onboarding Service using Python on the backend in a serverless and containerized architecture with a NextJS/React client frontend.
• Design, develop, and maintain scalable RESTful APIs and microservices using Python frameworks such as FastAPI or Flask.
• Build and support cloud-native solutions leveraging AWS services including Lambda, ECS Fargate, API Gateway, DynamoDB, S3, Secrets Manager, and CloudWatch.
• Work closely with the Lead React Engineer, Technical Architects, and Engineering teams to implement technical designs, architectural patterns, and coding standards.
• Collaborate with product managers, designers, and client stakeholders to translate business requirements into robust technical solutions.
• Design and implement integrations with internal client systems and external third-party APIs using REST, webhooks, and event-driven integration patterns.
• Apply software engineering best practices, including SOLID principles, Clean Architecture, Repository Pattern, Factory Pattern, Strategy Pattern, Dependency Injection, and other design patterns to create maintainable and extensible solutions.
• Implement resilient solutions using retry mechanisms, error handling strategies, circuit breaker patterns, dead-letter queues, and asynchronous messaging.
• Work within established development and release processes to ensure high-quality software delivery. Contribute to code quality, automated testing, performance optimization, and system reliability improvements.
• Support CI/CD deployment pipelines and collaborate with DevOps teams to ensure smooth and reliable application delivery.
• Contribute to documentation, knowledge sharing, and continuous improvement within the engineering team.

Requirements

• Professional software engineering experience.
• Strong commercial experience with Python using FastAPI, Flask, or similar backend frameworks.
• Extensive experience developing RESTful APIs, microservices, and backend services.
• Strong hands-on experience with AWS cloud services including ECS Fargate, Lambda, API Gateway, DynamoDB, S3, SNS, SQS, EventBridge, Step Functions, IAM, Secrets Manager, and CloudWatch.
• Strong experience with serverless deployment and architecture patterns.
• Experience developing and deploying containerized applications using Docker and AWS ECS/Fargate.
• Experience integrating with third-party APIs, enterprise platforms, and external services.
• Strong understanding of software design patterns, object-oriented programming principles, clean code practices, and distributed system design.
• Experience implementing API security using OAuth2, JWT, OpenID Connect, API Keys, and secure authentication/authorization mechanisms.
• Experience with relational and NoSQL databases such as PostgreSQL, MySQL, Aurora, or DynamoDB.
• Experience with Infrastructure as Code (Terraform, AWS CDK, or CloudFormation) is highly desirable.
• Good understanding of software deployment processes, application monitoring, logging, and environment management.
• Experience working in secure or regulated environments (e.g., healthcare, finance, government) is beneficial.
• Understanding of data protection, access control, and secure software development practices.
• Experience working within Agile/Scrum delivery environments.

Nice-to-Have Skills

• Experience with React/NextJS.
• Experience with automated testing frameworks such as Pytest, Unit Testing, Integration Testing, and API Testing.
• Exposure to WebSockets, event-driven architectures, or real-time data patterns.
• Familiarity with modern authentication approaches such as OAuth2, OpenID Connect, JWT, and AWS Cognito.
• Experience with OpenAPI/Swagger specifications and API lifecycle management.
• Experience with CI/CD tools such as GitHub Actions, Azure DevOps, Jenkins, or AWS CodePipeline.