Senior AWS Engineer

Cynet Systems • Malvern, PA

8h

About The Position

Our client is seeking a Senior AWS Engineer to extend an event-driven, serverless financial platform combining Python-based AWS Glue ETL pipelines with Node.js Lambda microservices. The role involves building and maintaining independently deployable services and data pipelines that process transaction files, reconcile financial data, and support reliable operations. Correctness, auditability, idempotency, security, and observability are central to the work.

Requirements

• Strong proficiency in Python 3.12 or later, including writing testable, well-structured ETL code.
• Strong proficiency in current-LTS Node.js, including ES6+, async/await, and JavaScript or TypeScript for AWS Lambda microservices.
• Experience designing and operating microservices architectures with single-purpose services, loose coupling, independent deployment, event contracts, and idempotency.
• Experience with AWS Glue, including PySpark, Glue 4.0, and DynamicFrames, and AWS Lambda using Python and Node.js runtimes.
• Experience with AWS Step Functions and Amazon States Language for workflow orchestration.
• Experience with AWS SAM or CloudFormation infrastructure as code and multi-environment deployment.
• Experience writing Oracle SQL, including complex joins and DML across transactional schemas, and stored procedure-like code patterns.
• Experience with DynamoDB key design, GSIs, conditional writes, and pagination.
• Experience with S3 event-driven architectures, EventBridge notifications, and data lake patterns such as Parquet.
• Strong testing discipline using pytest or unittest, Jest or Mocha, AWS service mocking with moto or aws-sdk-client-mock, and stubbing Spark/Glue runtime dependencies for offline unit tests.
• Experience with financial or transactional data where correctness, auditability, and idempotency are critical.
• CI/CD experience, ideally with Jenkins and multi-environment promotion gates.
• Familiarity with CloudWatch metrics and logs, Grafana, and operational dashboards.

Responsibilities

• Design, build, and maintain single-purpose, independently deployable AWS Lambda microservices within an event-driven architecture.
• Develop Node.js Lambda services for transaction file intake, validation, transformation, submission, and acknowledgement handling for JSON, XLSX, and CSV files.
• Build event-triggered services using S3 notifications, EventBridge, SQS, and API Gateway, with clearly defined service contracts.
• Integrate services with AWS using the AWS SDK for Node.js, including S3, DynamoDB, SNS/SES, Secrets Manager, and Step Functions.
• Manage Node.js dependencies and Lambda layers, bundle functions, and tune cold starts, memory, and timeouts.
• Define service boundaries and contracts, including event payloads, schemas, and S3 formats.
• Maintain and extend AWS Glue ETL jobs using PySpark and native Oracle JDBC to ingest, transform, and reconcile transaction history and position snapshot files.
• Build and troubleshoot Step Functions workflows for file validation, ingestion, reconciliation, and alerting.
• Design and maintain Python and Node.js Lambda functions for orchestration, validation, DynamoDB writes, and SNS/SES alerting.
• Write and optimize Oracle SQL against complex financial schemas.
• Manage DynamoDB models for transaction history, reconciliation status, and fund-level summaries, including GSIs and TTL-based retention.
• Implement robust error handling and transactional integrity, including per-record commit/rollback, idempotency, and duplicate detection.
• Apply retries, dead-letter queues, and idempotency keys to prevent duplicate processing of repeated S3 events.
• Own unit, integration, and smoke test suites and maintain or improve code coverage.
• Support CI/CD pipelines using Jenkins and AWS SAM/CloudFormation, including build, test, lint, and packaging of Node.js services.
• Build and maintain observability through structured CloudWatch logs and metrics, Grafana dashboards, and pipeline-health metric registries.
• Participate in security reviews and remediate findings, including SOC2-aligned issues, SQL injection risks, least-privilege IAM, KMS encryption, and Node.js dependency vulnerabilities.
• Create and maintain technical documentation, including architecture references, runbooks, deployment guides, and changelogs.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed