Senior Backend Engineer. Python and Go, 9+ years. Background in fintech and regtech, open to other domains. APIs, data pipelines, distributed systems. Based in Sofia, open to remote.

Python, Go, Django, FastAPI, Flask, PostgreSQL, Redis, Celery, Kafka, Docker, AWS, GCP, Azure, Linux.

ledger (Go, PostgreSQL) Double-entry ledger and payments API. Money as integer minor units, idempotency enforced by a unique index, append-only audit trail, and row-locked transfers. The test suite is the point: 50 simultaneous withdrawals against an account that can fund 10, asserting exactly 10 commits.

marketstream (Go, PostgreSQL) Real-time market data pipeline. Reads Binance's trade WebSocket, fans out across goroutines behind a bounded queue with a configurable overflow policy, batch writes to PostgreSQL, and serves OHLCV candles. Shutdown drains the queue instead of dropping it.

pgvector-rag (Python, FastAPI) Document search API using pgvector in PostgreSQL. OpenAI embeddings and chat with citations, Redis caching, and an eval script reporting retrieval hit-rate, latency, and cost.

elina (Python, Django, Celery) Hourly BTC/USD ingestion into PostgreSQL with a DRF read API. Ingestion is idempotent on the exchange's own timestamp, so polling faster than the exchange publishes does not duplicate rows. Constraints live in the database, the rate provider sits behind an interface, and the suite runs with sockets blocked.

synapse_stack (Python, Flask, React) File manager with Auth0 authentication. Every query is scoped to the calling user, and a test checks that an authenticated user asking for someone else's file gets a 404 while the owner still gets a 200. The browser suite runs against a local token issuer that mints real RS256 tokens, so it exercises signature, audience, and issuer checks rather than switching authentication off.

django_flask_kafka (Go, Django, Flask, Kafka) Four services, each owning its database, kept consistent by events rather than by calling each other. Writes go into a transactional outbox, so the API keeps accepting them while Kafka is down and they drain when it returns. Consumers deduplicate, so a replay is a no-op. A Go service issues RS256 tokens and the Python services verify them locally against its JWKS, with revocations broadcast over Kafka.

• live-metrics Binance trades through Redpanda into TimescaleDB and Redis, with a live candlestick dashboard.
• real-time-pipeline Event-driven log pipeline on Kafka, Celery, Redis, and PostgreSQL, with a FastAPI dashboard.
• go_message_dispatcher Queue worker in Go using FOR UPDATE SKIP LOCKED, with a per-cycle Redis lock so only one instance processes each cycle when several run.
• tricolor Concurrent tri-color mark and sweep garbage collector in Go, implementing the algorithm rather than calling runtime.GC. No dependencies, no cgo, no unsafe; a write barrier holds the invariant while mutators keep running.
• peephole Peephole optimizer for CPython 3.11 bytecode. Disassembles a .pyc, builds a basic block CFG, folds constants, drops dead blocks, reduces strength, and eliminates redundant loads, then reassembles a valid .pyc.
• jit JIT compiler for an integer subset of Python in Go. A recursive descent parser, an SSA-like IR, and x86-64 code generation into mmap executable memory, called from pure Go with no cgo. Linux amd64.

• darabi.website
• linkedin.com/in/hamidreza-darabi
• hamidreza.darabi@hotmail.com