Profile

Senior Backend Engineer with 9+ years of expertise in Python, AWS event-driven systems, and workflow orchestration. Proven track record building production-grade data pipelines, microservices, and third-party integrations — including ServiceNow, SQS/EventBridge automation, and Airflow-based ETL systems. Experienced technical leader in Agile teams with a strong foundation in clean-code principles, observability, and end-to-end DevOps ownership. Adept at translating complex operational workflows into reliable, scalable backend services.

Expertise
AWS Services
  • Lambda · SQS · SNS · EventBridge
  • Step Functions · API Gateway
  • Glue · Athena · S3 · Redshift
  • DynamoDB · KMS · IAM · CloudWatch
  • Fargate · ECS · EC2 · DLQ
IaC & DevOps
  • Terraform · AWS CDK
  • CloudFormation · StackSets
  • GitHub Actions · GitLab CI
  • Docker · Serverless Framework
Databases
  • DynamoDB · PostgreSQL · MySQL
  • Elasticsearch · MemSQL
  • AWS RDS · Redshift
Integrations
  • ServiceNow · REST APIs
  • Async workflows · retry logic
  • ELK Stack · Logstash · Kibana
Experience
Senior Python & AWS Developer Dec 2023 – Present
Apex Systems  ·  Client: Centene
Python · Lambda · SQS · SNS · EventBridge · Step Functions · Glue · DynamoDB · S3 · KMS · Terraform · Flask · ServiceNow · API Gateway
  • Architected a centralized Error Handler: EventBridge captures pipeline failures, triggers Lambda processors that classify, encrypt (KMS), persist to S3, and auto-create ServiceNow incidents — eliminating manual error triage.
  • Designed event-driven microservices using SQS → Lambda → DynamoDB with DLQ handling, retry logic, and full CloudWatch observability.
  • Built REST APIs with FastAPI/Flask on API Gateway + Lambda with clean-code principles and pytest coverage.
  • Authored reusable Terraform IaC modules for multi-account deployments via CloudFormation StackSets, enforcing KMS encryption and IAM least-privilege.
  • Built multi-vendor ETL ingestion module (S3 + EventBridge + Lambda + Glue/PySpark) packaged as a reusable Python library with Poetry and a Terraform module.
Senior Python Developer & Technical Leader Aug 2022 – Dec 2023
Bold.SAS
Python · Lambda · SQS · Step Functions · AWS CDK · API Gateway · DynamoDB · S3 · Flask · Domain-Driven Design
  • Led the Acquiring Banking Team — designed event-driven service architecture for high-volume payment network messaging using SQS + Step Functions with idempotency and retry guarantees.
  • Drove migration from legacy database schemas to Domain-Driven Design, improving system reliability, scalability, and maintainability of microservices.
  • Mentored engineers on AWS messaging patterns, code quality standards, and test-driven development; conducted systematic code reviews across the team.
  • Served as technical decision-maker aligning engineering execution with product stakeholders; contributed to architectural design sessions and sprint planning in Agile environment.
Senior Data Engineer & AWS Developer Sep 2021 – Aug 2022
Zebrands
Python · Lambda · SQS · SNS · EventBridge · Glue · Athena · S3 · QuickSight · ECR · CloudFormation · GitHub Actions · Docker · Selenium · Pandas · PyArrow
  • Architected an event-driven data pipeline using EventBridge → Lambda → S3 → Glue → Athena, replacing over-provisioned batch jobs with real-time processing — reducing AWS costs by 75%.
  • Implemented pub/sub patterns with SNS and SQS for decoupled, scalable data ingestion across multiple internal systems and external APIs (Amazon Vendor Central).
  • Built and managed Apache Airflow DAGs for scheduled/event-driven ETL including vectorization pipelines.
  • Automated CI/CD pipelines with GitHub Actions, Docker, and ECR; configured CloudWatch alarms and dashboards for proactive pipeline health monitoring and incident detection.
  • Built Selenium-based automated ETL scrapers integrating external data sources and delivering clean datasets to downstream analytics consumers.
  • Produced QuickSight observability dashboards translating service telemetry and business data into actionable executive-level insights.
Backend Developer & Data Engineer Jul 2019 – Sep 2021
Elasbit – Fivana Project
Python · Lambda · SQS · SNS · Step Functions · API Gateway · AppSync · DynamoDB · Redshift · Elasticsearch · Logstash · Kibana · CloudFormation · Serverless · C# · Ruby
  • Developed event-driven microservices and REST APIs in Python on AWS, including SQS/SNS-based messaging for asynchronous business workflows across distributed services.
  • Designed and operated ETL pipelines with the ELK stack; authored a custom Logstash input plugin to extract data from Elasticsearch indexes and feed downstream reporting.
  • Built analytics dashboards in Grafana and AWS QuickSight; created reporting views and stored procedures in MemSQL for business intelligence reporting.
  • Contributed to code reviews, Agile sprint delivery, and system documentation in a distributed international engineering team.
Python Developer Nov 2018 – Jul 2019
Merchise Autrement
Python 3.x · Odoo
  • Developed collections and advance payment modules for Odoo; migrated from Odoo 10 to Odoo 12.
Backend Developer Sep 2016 – Nov 2018
Center for Genetic Engineering and Biotechnology (CIGB)
C# · .NET · PostgreSQL · Clean Architecture
  • Built a controlled-environment management system and desktop application for incubator data processing using Clean Architecture and PostgreSQL.
Personal Projects
Open Source
LeaseAI ernsoler/leaseai

Upload a PDF lease agreement — get a structured AI risk report in under 90 seconds.

Python 3.12 AWS CDK Lambda SQS DynamoDB S3 Claude API React TypeScript
  • Async job pipeline: presigned S3 upload → SQS → Lambda processor → DynamoDB, with frontend polling and 90s p95 turnaround.
  • Multi-provider AI routing (Claude, OpenAI, Gemini, Ollama) with Pydantic validation gate — bad AI responses mark the job failed rather than storing corrupt data.
  • Fully deployable serverless SaaS with CDK IaC, CloudWatch alarms, DLQ monitoring, and GitHub Actions CI.
Reference Arch
DDD · Python · AWS ernsoler/ddd-python-aws

Production-grade DDD reference on AWS Serverless — aggregates, repositories, unit of work, and domain events in a hexagonal architecture.

Python 3.12 DDD Lambda DynamoDB EventBridge Serverless Pydantic v2 moto
  • Domain layer has zero AWS dependencies — infrastructure fully isolated behind Protocol-based adapters, making every business rule independently testable.
  • Generic DynamoDB repository with optimistic locking (version field), atomic UoW transactions, and post-commit EventBridge event publishing.
  • Test suite uses moto to spin up real DynamoDB + EventBridge in-process with the exact same schema as the IaC — no mocks, full fidelity.