HI, I'M
Yusuf Erkan Darıyemez
Senior Backend Developer
I build scalable backend systems with Go and PostgreSQL — payment flows, integrations and data-heavy production applications.
About
I'm a senior backend developer with six years of production experience, almost all of it in Go and PostgreSQL. I've designed and built the backend architecture of ERP, CRM, donation-management, accounting and payment systems, established team-wide engineering standards, and led a seven-person cross-functional team through mentoring and code review.
The systems I build move real money and real data: payment provider integrations, accounting and reconciliation flows, multi-tenant platforms, audit trails, and the reporting paths on top of them. My bias is correctness first — explicit code, layered architecture, carefully modeled schemas, and query performance that is measured rather than guessed.
On the side I maintain open source Go libraries and tools, extracted from patterns I kept rebuilding at work — including standalone guards for the parts of operations nobody usually watches: query plans, data freshness, webhook delivery.
What I do
Backend systems & APIs
RESTful APIs, background jobs, third-party integrations with idempotency and retry discipline.
Money & correctness
Payment flows, double-entry accounting, bank reconciliation — no floats near money, everything provable.
PostgreSQL reliability
Query plan regressions, data freshness, integrity — tools that catch problems in CI, not at 3 AM.
Open source
selected workgo-efatura
↗Turkish e-invoice (GİB, UBL-TR): document builder, schematron-derived validation, XAdES signing.
go-ledger
↗Double-entry accounting engine: integer money, balanced transactions, append-only journal.
hookkeep
↗Self-hosted webhook inbox: receive, verify, persist, deliver with retries, replay anything. PostgreSQL-native, embedded Vue UI.
monup
↗terraform plan for monitoring: point it at a Docker host, it discovers what's running and generates a tailored Prometheus + Grafana stack as committable config.
pg-plan-guard
↗Catch query plan regressions in CI, not at 3 AM: snapshot EXPLAIN plans into a committed lock file, diff their shapes on every PR.
data-watchdog
↗Your system is up; is your data alive? Freshness / volume / integrity checks for operational Postgres, read-only by design, every alert ships with evidence SQL.
Writing
Production war stories — distributed locks that weren't, event buses that lost messages, floats that touched money. Mostly Turkish, some English.
Building a system?
Write me about backend architecture, payment infrastructure or PostgreSQL.
yusuf.erkamyed@gmail.com