Alper Soy, Backend Software Engineer Backend systems that handle payments, bookings and clinical workflows.
I build and run the APIs, data models, background jobs, tests and deployments behind them. Mostly Node.js, NestJS, TypeScript and PostgreSQL; .NET and C# where a platform calls for it.
Client: Clear contracts: versioned REST endpoints, validated input and OpenAPI docs the frontend can build against before the backend lands.
API: Identity and roles at the edge, then transactions and row locks wherever two requests must not race.
Queue: Anything slow or unreliable leaves the request path: queued jobs with retries and backoff, scheduled work, deduplicated by id.
Worker: Payment webhooks, notifications, document pipelines and sync jobs that are idempotent, observable and safe to rerun.
Database: Data models that survive change: migrations, indexes, soft delete and versioning, and caches with clear invalidation.
The same shape sits behind a booking, a payment or a clinical case: a request is validated, work that can wait goes to a queue, a worker finishes it, and every state change ends up in a database that will still make sense in a year.
Selected work
For Physician
2026 - presentFor Physician
Clinical consultation platform for physicians, with AI assistance
A physician describes a clinical case, gets a preliminary assessment from an AI assistant and can escalate the case to a specialist. Available as iOS, Android and web apps.
- Clinical case workflow between physicians and specialists
- AI assistant features and account lifecycle flows
- Automated tests, database migrations and localization
For Physician stack: NestJS, TypeScript, PostgreSQL, Redis, Docker, Kubernetes
Bamep Inc.
2021 - 2026ScaleUpStream
Platform connecting startups with investors, incubators and service providers
Startups, investors, incubators, institutions and service providers each get a page and interact through investment questionnaires with weighted scoring, pitch events, cohorts, paid content and a service marketplace. A NestJS and PostgreSQL backend with Stripe billing, domain events and a worker process.
- Stripe payments, subscriptions, metered usage and Connect accounts for sellers
- Domain events and queues behind a dedicated worker
- Weighted scoring engine for startup submissions with a record of every score
ScaleUpStream stack: NestJS, TypeScript, PostgreSQL, Sequelize, Redis, Bull, Stripe, Zoom API, AWS S3, Heroku, GitHub Actions
Crea Inc.
2022 - 2024GiddyUp
Booking marketplace for travelers with horses
Hosts list farms and ranches with places for horses and their people; guests search along their driving route, book, pay and message the host. NestJS on PostgreSQL with PostGIS, Stripe Connect payments and a CQRS application layer.
- Search along a driving route with PostGIS
- Booking and payment lifecycle driven by Stripe webhooks
- Distributed lock against double bookings; end-to-end tests on a disposable database
GiddyUp stack: NestJS, TypeScript, PostgreSQL, PostGIS, TypeORM, Redis, Stripe Connect, Auth0, AWS S3, Mapbox, Heroku
Crea Inc.
2022 - 2024Edvisorly
Transfer planning platform for community college students
Students plan their courses term by term against transfer requirements, follow universities, apply to partner schools inside the app and chat with them. A NestJS and MongoDB backend with a separate worker for queues, schedules and university integrations.
- One codebase, three processes: HTTP API, background worker and an operations CLI
- Pipelines that deliver student inquiries and applications to university systems
- Unit and end-to-end tests on an in-memory MongoDB with a coverage threshold
Edvisorly stack: NestJS, TypeScript, MongoDB, Mongoose, Redis, Bull, Auth0, AWS S3, Docker, Heroku
Kalder, via Crea Inc.
2022 - 2023Kalder
Membership and loyalty platform for brands
Brands issued NFT membership cards, ran quests that paid rewards in brand tokens, hosted events with QR check-in and handed members Apple Wallet passes. A NestJS and MySQL backend with a background worker, white-label support for many brands and ownership checks on chain.
- Apple Wallet pass pipeline from mint to signed pass to branded email
- QR check-in that verifies a pass or a signed wallet message, then ownership on chain
- Self-healing sync between mint records and the chain
Kalder stack: NestJS, TypeScript, MySQL, TypeORM, Redis, Bull, Apple Wallet, ethers, AWS S3, Heroku
Personal projects
2025
TopicFlow
Discussion platform with topics, posts and threaded comments
Users sign in with GitHub, create topics and posts, and reply in nested threads. Next.js 15 App Router with React 19 server actions, Prisma on PostgreSQL and Auth.js, deployed on Vercel.
- Server actions with useActionState and zod validation
- Recursive threaded comments rendered from one cached query per request
- Streaming with Suspense; Prisma migrations applied at build time
TopicFlow stack: Next.js, React, TypeScript, Prisma, PostgreSQL, Auth.js, Tailwind CSS, Vercel
2024
Activity Hub
Event planning app with live discussion
Users create and join activities, follow each other and discuss every event in a live comment thread. ASP.NET Core 8 with Clean Architecture layering and MediatR handlers, SignalR for live comments, a React client, deployed on Azure.
- Clean Architecture layers: API, Application, Domain, Infrastructure, Persistence
- MediatR command and query handlers
- SignalR hub for live comments; ASP.NET Identity with JWT
Activity Hub stack: .NET 8, C#, ASP.NET Core, MediatR, SignalR, React, Azure
Experience
- Present
Istanbul, Türkiye (remote)
Software Engineer, For Physician
Backend engineer on a clinical consultation platform for physicians, with AI assistance.
- Backend engineer on the clinical case workflow between physicians and specialists.
- Work on the AI assistant features and the account lifecycle flows.
- Maintain the automated test suites, database migrations and localization.
Technologies at For Physician: NestJS, TypeScript, PostgreSQL, Redis, Docker, Kubernetes
Case studies: For Physician
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San Francisco, CA (remote)
Software Engineer, Bamep Inc.
Employer of record for the client engagements below; product work on ScaleUpStream, Bamep's own platform.
- Developed backend services with NestJS, .NET Core, PostgreSQL and Redis for ScaleUpStream, a platform connecting startups, investors and service providers.
- Implemented the Stripe integration end-to-end: customers, subscriptions with promotion codes, metered usage, Connect onboarding for sellers and the payment webhooks.
- Optimized PostgreSQL queries with indexing and caching strategies.
Technologies at Bamep Inc.: NestJS, .NET Core, PostgreSQL, Redis, Stripe, AWS, GitHub Actions
Case studies: ScaleUpStream
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San Francisco, CA (remote)
Software Engineer, Crea Inc. via Bamep Inc.
Client engagement through Bamep; backend engineer on GiddyUp and Edvisorly.
- Developed and maintained backend services with NestJS, PostgreSQL, MySQL, MongoDB and Redis.
- Worked in modular monolithic codebases with clear module boundaries, keeping them maintainable and extensible.
- Designed database schemas and query optimizations that reduced query execution time.
Technologies at Crea Inc.: NestJS, PostgreSQL, MongoDB, MySQL, Redis, AWS
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Brooklyn, NY (remote)
Software Engineer, Kalder via Crea Inc.
Client engagement through Crea; one of the main backend contributors to Kalder's membership platform for brands.
- Developed backend services with NestJS, MySQL and Redis: a REST API and a background worker serving many brands from one codebase.
- Built the quest engine (experiences with proofs, waitlists, quotas and token rewards), the email notification system and the whitelist and waitlist flows.
- Worked on the Apple Wallet pass pipeline and the QR check-in flow with NFT ownership checks on chain.
Technologies at Kalder: NestJS, MySQL, TypeORM, Redis, Bull, Apple Wallet, AWS S3
Case studies: Kalder
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Istanbul, Türkiye
Software Engineer, Earnado
- Developed Node.js applications backed by MySQL through the Sequelize ORM.
- Added Redis caching, speeding up data retrieval and reducing server load.
- Designed and built REST API endpoints.
Technologies at Earnado: Node.js, MySQL, Sequelize, Redis
About
I am a backend engineer working mostly on NestJS services backed by PostgreSQL, MongoDB and Redis. The systems I have worked on handle bookings and payments, clinical workflows, background pipelines and external integrations, together with the tests and CI that keep them shippable.
I care about the parts of backend work that do not show up in a feature list: data models that survive change, transactions and locks that prevent bad states, observability, and test suites that make refactoring safe.
Capabilities
- Backend
APIs that stay consistent under change: versioned contracts, validation, documentation.
Node.js, TypeScript, NestJS, .NET Core, C#, REST API design, OpenAPI / Swagger
- Data
Schemas and queries that survive growth: indexes, migrations, transactions, caching.
PostgreSQL, PostGIS, MySQL, MongoDB, MSSQL, Redis, TypeORM, Sequelize, Mongoose, Entity Framework Core
- Async work and integrations
Work that leaves the request path: queues, schedulers, webhooks and payment flows that are safe to retry.
Bull / BullMQ, Cron workers, Domain events, Stripe (Payments, Connect, subscriptions), Auth0, Keycloak, AWS S3, Webhooks
- Architecture
Modular monoliths with clear boundaries, and the locks and versions that prevent bad states.
Modular monoliths, CQRS, Layered architecture, Caching strategies, Distributed locks, Soft delete and versioning
- Cloud and delivery
Containers, CI pipelines and deployments that a small team can run.
AWS, Azure, Docker, Kubernetes, Heroku, GitHub Actions, Vercel
- Testing and quality
Test suites that make refactoring safe, from unit tests to end-to-end runs against real databases.
Jest, Supertest, End-to-end suites with disposable databases, Coverage gates, Load testing, ESLint, Prettier, husky
- Frontend, when needed
React and Next.js for internal tools and product surfaces when the team needs them.
React, Next.js, Angular, Tailwind CSS