card-auth-simulator
A small issuer-side authorization engine: rule pipeline, ISO 8583 response codes, balance holds, velocity limits and idempotent replays.
View code →helen@dev ~ %
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Hello, I'mHelen Aramyan
Senior Java & Go Developer | Lead Engineer
10+ years building enterprise-grade distributed systems in fintech, payments, and cloud infrastructure.
01. About Me
When a bank needs to migrate a million cardholders seamlessly, or an enterprise platform needs its monolith rearchitected into 30+ microservices, or Visa and Mastercard integrations need to work flawlessly in production — that's where I come in.
I'm a Senior Java & Go Developer and Lead Engineer with over a decade of experience building systems that handle millions of transactions. Currently leading backend engineering at a licensed digital banking platform processing payments across multiple markets.
Previously at Adobe, I worked on Workfront and Fusion — decomposing monoliths, building enterprise integrations (Outlook, Salesforce, Jira), owning the full DevOps lifecycle, and cutting deployment times from 4 hours to 20 minutes.
I thrive on complexity: payment schemes, regulatory compliance, high-throughput event-driven systems, and leading international engineering teams of up to 10 engineers.
Now: leading backend for card issuing and payments, and bringing AI into the engineering workflow: RAG pipelines, LangGraph agents, MCP servers and LLM integrations on AWS Bedrock, Vertex AI and the Anthropic API.
How I work: DDD and clean architecture, event-driven design with sagas and CQRS where they earn their keep, strong observability from day one, and a QA mindset from my test-automation roots (ISTQB certified).
0+Years Experience
0M+Cardholders Migrated
0+Microservices Built
0K+ TPSPayment Processing
0M+Cardholders on Platform
0M+Daily API Calls (Fusion)
02. Experience
Lead Senior Java / Go Developer · Team Lead
Licensed Digital Banking Platform · Remote
Leading backend engineering for a licensed card issuing platform serving 20M+ cardholders across multiple markets.
- Led full migration of 1M+ cardholders between issuing banks — zero downtime, full regulatory compliance
- Architected integrations with Visa (VTS, Visa Direct), Mastercard (MDES, Mastercard Send), MPGS, UnionPay and JCB
- Built real-time payment processing pipelines handling 10K+ TPS
- Designed bank-to-bank settlement, reconciliation and dispute management pipelines
- Implemented 3DS2 authentication, tokenization, and PCI-DSS compliant card lifecycle management
- Integrated core banking systems for ledger, KYC and transaction management
- Designed webhook-driven event systems for partner bank onboarding
- Lead a team of up to 10 engineers: architecture, code reviews, hiring and delivery
- Introduced AI-assisted engineering: RAG pipelines, LLM integrations and agentic tooling (Bedrock, Vertex AI, Anthropic API)
Java 17+GoSpring BootKafkaPostgreSQLRedisAWSGCPKubernetesDockerArgoCDCamundaPineconeBedrock
Software Engineer, Core Team (Java & Go)
Adobe — Workfront Fusion
Core backend engineer on the workflow automation platform connecting 200+ enterprise applications.
- Led design and implementation of production connectors: Microsoft Outlook, Salesforce, Jira, Workday and more
- Architected connector framework handling 5M+ daily API calls across customer tenants
- Built OAuth2 and API key authentication flows for third-party integrations
- Drove Go adoption for high-performance microservices alongside the Java codebase
- Mentored junior and mid-level engineers, led code reviews and architecture discussions
- Collaborated with product and design teams across US, EU and India
JavaGoSpring BootJSAWSDockerKubernetesRESTOAuth2PostgreSQLRedis
Software Engineer II
Adobe — Workfront Fusion
Backend and DevOps on the Fusion integration platform.
- Reduced deployment time from 4 hours to 20 minutes through CI/CD automation
- Rewrote critical legacy Java services — 60% faster responses
- Owned the DevOps lifecycle: Jenkins pipelines, Docker, AWS infrastructure, monitoring
- Implemented feature toggles, A/B testing infrastructure and canary deployments
JavaGoSpring BootAWSDockerKubernetesJenkinsKafkaTerraform
Software Engineer → Software Engineer II
Adobe Workfront
Backend engineer on Workfront — an enterprise work management platform processing millions of daily requests.
- Led disaggregation of the monolith into 30+ independently deployable microservices
- Rewrote legacy Java code — reduced technical debt by 40%, test coverage from 45% to 85%
- Built versioned RESTful APIs with backward compatibility
- Optimized high-load PostgreSQL and Oracle queries — reduced p95 latency by 50%
- Enhanced CI/CD with automated testing, SonarQube static analysis and deployment gates
- On-call rotations and production incident response
JavaSpring BootHibernatePostgreSQLOracleReactJenkinsDockerSonarQubeDataDog
Software Engineer / Java
Webb Fontaine
Customs and trade automation for governments across 10+ countries.
- Developed Java automation frameworks for customs declaration processing and trade compliance
- Built financial modules for duty calculation, tariff classification and revenue management
- Integrated with government regulatory systems and cross-border data exchange protocols
- Designed batch pipelines for high-volume customs transaction data
JavaSpringRESTOracle DBLinuxMavenJUnit
Software Engineer
IBM ISTC
Built FoodMiX — an AI-powered recipe recommendation startup, inside IBM's startup incubator.
- Full-stack app suggesting recipes from available ingredients using ML-based scoring
- REST services for ingredient matching, recipe scoring and preference learning
- Ingestion pipelines normalising 10K+ recipes
- Presented the product at IBM ISTC demo days to investors and mentors
JavaSpringRESTPostgreSQLLinuxML
03. Tech Stack
Languages
Java
Go
SQL
Python
Cloud & DevOps
AWS
Kubernetes
Docker
Terraform
Frameworks
Spring Boot
Kafka
gRPC
REST APIs
Databases
PostgreSQL
Redis
Oracle
MongoDB
Payments & Fintech
Visa / Mastercard
3DS2 / Tokenization
PCI-DSS
Core Banking
Architecture & AI
DDD / CQRS / Saga
Event-Driven
RAG Pipelines
LLM Integration
Messaging & APIs
Kafka / NATS
RabbitMQ / SQS / SNS
gRPC / Protobuf / Avro
GraphQL
Observability
Datadog
Prometheus / Grafana
OpenTelemetry
Sentry
AI Engineering
LangChain / LangGraph
MCP Servers & Agents
Vector DBs (Qdrant, Pinecone)
Bedrock / Vertex AI
04. Key Achievements
Bank-to-Bank Migration
Led the full migration of 1M+ cardholders between issuing banks with zero downtime and full regulatory compliance across multiple markets.
Payment Scheme Integrations
Architected and delivered direct integrations with Visa (VTS, Visa Direct), Mastercard (MDES, Mastercard Send), MPGS, and UnionPay.
10K+ TPS Processing
Built real-time payment authorization pipelines handling 10,000+ transactions per second with sub-100ms latency.
Monolith to Microservices
Decomposed Adobe Workfront's monolith into 30+ independently deployable microservices used by Fortune 500 clients.
Deployment: 4h to 20min
Automated the entire CI/CD pipeline, cutting deployment time by 92% and enabling 3+ releases per day.
Enterprise Connectors
Built production integrations for Adobe Fusion: Outlook, Salesforce, Jira, Workday — handling 5M+ daily API calls.
3DS2 & Tokenization
Delivered 3DS2 cardholder authentication, VTS / MDES tokenization and PCI-DSS compliant card lifecycle management.
Coverage 45% to 85%
Rewrote critical legacy Java code at Workfront, cutting technical debt by 40% and nearly doubling test coverage.
AI in Engineering
Building RAG pipelines, LangGraph agents and MCP servers to bring AI into payments engineering and operations.
05. Projects
Payments tooling and side projects I build outside of work.
iso8583-go
Dependency-free ISO 8583 packer and unpacker with primary and secondary bitmaps, LLVAR/LLLVAR fields and a demo authorization switch.
View code →settlement-recon-cli
Reconciles authorizations against scheme clearing records: tiered matching, FX tolerances, late presentments, duplicates and net settlement per currency.
View code →payment-webhooks
HMAC-signed payment webhooks with at-least-once delivery, exponential backoff, dead-letter queue and replay.
View code →idempotency-spring-starter
Spring Boot starter that adds @Idempotent to REST endpoints so client retries never double-charge. In-memory and Redis stores.
View code →fraud-triage-agent
Triage agent for suspicious card transactions: rule-based risk scoring, Claude investigation with tools via Anthropic API or AWS Bedrock, guardrails, and human-in-the-loop review.
View code →decline-code-assistant
Agent on Claude that explains why card transactions declined, grounded in a curated knowledge base with citations. Also runs as an MCP server.
View code →luhn-bin-kit
Luhn validation, BIN and scheme detection, PAN masking and test-card generation as a Go library and CLI.
View code →pytest-influxdb plugin
Open-source pytest plugin that streams live test results to InfluxDB for dashboards and reporting tools.
View code →06. Education & Certifications
MSc Cybersecurity
Security engineering foundations behind PCI-DSS, tokenization, 3DS2 and OAuth2 work in payments.
National Polytechnic University of Armenia
University studies in engineering and computer science in Yerevan.
Oracle Certified Java Developer (OCA)
Oracle certification for Java SE programming.
ISTQB Certified Tester
Testing and quality engineering certification from my automation-framework years.
Recognition Award · Webb Fontaine
Award received at Webb Fontaine for work on customs and trade automation.
Ownership Acknowledgment · Workfront
Ownership recognition received at Workfront, an Adobe company.
07. Blog
Thoughts on engineering, payments, and distributed systems.
How We Migrated 1M Cardholders With Zero Downtime
A deep dive into the architecture and strategies behind migrating a million cardholders between issuing banks without a single second of service interruption.
Read more →Event-Driven Settlement Systems in Fintech
Why event-driven architecture is the right choice for building settlement and reconciliation systems, and the patterns that make it work at scale.
Read more →When to Use Go Over Java in Payment Systems
After years of working with both languages in production payment systems, here's my framework for choosing the right tool for each microservice.
Read more →