Senior Network Software Engineer – Python & Go

Job Description

For one of our clients, we are looking for a Senior Network Software Engineer – Python & Go (m/f/n).Offer100% remoteRate: 160 - 195 PLN/h net+VATB2B contract via SHIMIStart: 01.10Core languages- Go: concurrent services, UDP/TCP servers, high-throughput decode loops, profiling with pprof.- Async Python: asyncio internals (event loop, tasks, cancellation, backpressure), async HTTP client/server, multiprocess worker pools.Quality discipline- Static typing (mypy / golangci-lint), formatters/linters, pre-commit gates.- Async unit tests, snapshot tests for decoders, load tests in CI.- Dependency/CVE hygiene as a reflex, reproducible pinned builds.Networking depth- L2/L3/L4 headers by hand. VLANs, MAC/IP semantics, TCP flags, MTU/fragmentation, IPv4 + IPv6.- Flow telemetry protocols: IPFIX (RFC 7011), NetFlow v5/v9, sFlow v5. Template-based decode, sampling rates, sequence gaps and loss handling.- Packet capture and crafting; reading pcap as a primary debugging tool.- Network device automation over SSH/CLI and vendor APIs (Cisco, Arista, Juniper, Palo Alto). Idempotent config push, drift detection.Data movement- Protocol Buffers: schema design, evolution, codegen. Fast JSON/binary codecs for hot paths.- Kafka producer/consumer semantics: partitioning, acks, batching, compression, SASL/Kerberos, lag diagnosis. NSQ/NATS a plus.- Columnar/timeseries sinks (ClickHouse or similar).Performance engineering- Profiling as routine, not incident response. Allocation and GC pressure, lock contention, zero-copy paths.- Right data structures: LPM/Patricia tries for subnet lookup, LRU caches, fast hashing. Can explain the tradeoff, not just name it.- Load generation and sustained-throughput testing.Systems and delivery- Linux internals: sockets, epoll, sysctl tuning for high packet rates, cgroups/resource limits.- eBPF a strong plus.- Containers + Kubernetes: multi-stage builds, fast inner-loop dev, manifests.- Shipping a self-contained binary to customer infrastructure: static/frozen builds, deb/rpm packaging, upgrade and rollback paths.- IPC patterns (ZeroMQ or equivalent).Distributed state- Cache/state-sync design, eventual consistency, reconnect-and-resync after long disconnects, idempotent replay.Identity and cloud integrations (plus)- Windows/AD plumbing: WinRM, SMB, Kerberos.- A major cloud SDK (Azure or AWS) for asset and log ingestion.