Senior AWS Engineer

Job Title: Senior AWS Engineer

Job Location: Malvern, PA

Job Type: Contract

Pay Range: $53.00hr - $58.00hr

Job Overview:

Our client is seeking a Senior AWS Engineer to extend an event-driven, serverless financial platform. The platform combines Python-based AWS Glue ETL pipelines with Node.js Lambda microservices.

Responsibilities:

• Design, build, and maintain independently deployable microservices (single-purpose AWS Lambda functions) within an event-driven architecture.
• Develop and maintain Node.js (ES6+/async-await) Lambda microservices for file intake, validation, transformation, submission and acknowledgement handling of transaction files (JSON, XLSX, CSV).
• Build event-driven Node.js services triggered by S3 event notifications, EventBridge, SQS and API Gateway, with clear contracts between services.
• Use the AWS SDK for Node.js (v3 preferred) to integrate with core AWS services such as S3, DynamoDB, SNS/SES, Secrets Manager and Step Functions.
• Manage dependencies, Lambda layers, bundling and cold start/memory/timeout tuning for Node.js functions.
• Define clean service boundaries and contracts (event payloads, schemas, S3 formats) enabling independent development and deployment.
• Maintain and extend AWS Glue ETL jobs (PySpark + native Oracle JDBC) that ingest, transform, and reconcile daily transaction history and position snapshot files.
• Build and troubleshoot Step Functions workflows (ASL state machines) orchestrating multi-stage pipelines: file validation, ingestion, reconciliation, alerting.
• Design and maintain Lambda functions (Python and Node.js) for lightweight orchestration, file validation, DynamoDB writes, and SNS/SES alerting.
• Write and optimize Oracle SQL (native JDBC and Lambda-proxied) against a complex financial schema.
• 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 (per-record commit/rollback, idempotency, duplicate-detection) for financial data where silent failures are unacceptable.
• Apply retries, dead-letter queues and idempotency keys (for example, a file ID checked with DynamoDB conditional writes) so S3 events delivered more than once never cause duplicate processing.
• Own unit, integration, and smoke test suites (pytest/unittest, Jest/Mocha, moto and aws-sdk-client-mock for AWS mocking) and maintain/improve code coverage.
• Support CI/CD pipelines (Jenkins, AWS SAM/CloudFormation), including build, test, lint and packaging of Node.js services.
• Build and maintain observability: structured CloudWatch logging/metrics, Grafana dashboards, and metric registries for pipeline health.
• Participate in security reviews (SOC2-aligned findings, SQL injection guards, least-privilege IAM, KMS encryption) and remediate findings, including Node.js dependency vulnerability management (npm audit).
• Produce and maintain technical documentation (architecture references, runbooks, deployment guides, changelogs).

Required Skills & Experience:

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

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• Medical, Dental, and Vision Insurance
• 401(k) Retirement Plan
• Health Savings Account (HSA)
• Disability Insurance (Short-Term and Long-Term)
• Life and AD&D Insurance
• Paid Sick Leave (where required by applicable state or local law)
• Supplemental Insurance Plans
• Identity Theft Protection
• Pet Insurance
• Employee Wellness Programs
• Employee Assistance Program (EAP)
• Career Growth and Professional Development Opportunities