Senior AWS Engineer

Cynet Systems•Malvern, PA

About The Position

The organization 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 develops and operates independently deployable services and multi-stage data workflows for transaction files and financial records, with a strong focus on correctness, auditability, idempotency, testing, security, and operational observability. The engineer will build and maintain Node.js and Python Lambda functions, AWS Glue ETL jobs, Step Functions workflows, and supporting AWS infrastructure. The work includes ingesting, validating, transforming, reconciling, and reporting on transaction history and position snapshot files; managing Oracle and DynamoDB data; supporting CI/CD; and maintaining technical documentation.

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, including 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.
Oracle SQL skills, including complex joins, DML across transactional schemas, and stored-procedure-like code patterns.
DynamoDB experience with 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 offline unit testing with stubbed Spark/Glue runtime dependencies.
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 independently deployable, single-purpose AWS Lambda microservices within an event-driven architecture.
Develop Node.js Lambda microservices for transaction-file intake, validation, transformation, submission, and acknowledgement handling for JSON, XLSX, and CSV files.
Build event-driven Node.js services triggered by S3 event notifications, EventBridge, SQS, and API Gateway, with clear service contracts.
Use the AWS SDK for Node.js to integrate with AWS services including S3, DynamoDB, SNS/SES, Secrets Manager, and Step Functions.
Manage 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, to enable independent development and deployment.
Maintain and extend AWS Glue ETL jobs using PySpark and native Oracle JDBC to ingest, transform, and reconcile daily transaction history and position snapshot files.
Build and troubleshoot Step Functions workflows that orchestrate file validation, ingestion, reconciliation, and alerting.
Design and maintain Python and Node.js Lambda functions for orchestration, file validation, DynamoDB writes, and SNS/SES alerting.
Write and optimize Oracle SQL against a complex financial schema using native JDBC and Lambda-proxied access.
Manage DynamoDB data 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 when S3 events are delivered more than once.
Own unit, integration, and smoke test suites and maintain or improve code coverage.
Support CI/CD pipelines, including build, test, lint, and packaging of Node.js services.
Build and maintain observability through structured CloudWatch logging and metrics, Grafana dashboards, and metric registries for pipeline health.
Participate in security reviews and remediate findings, including SOC2-aligned issues, SQL injection safeguards, least-privilege IAM, KMS encryption, and Node.js dependency vulnerabilities.
Produce and maintain architecture references, runbooks, deployment guides, and changelogs.