Backend Engineer - Europe/UK Timezone

Posthog1 weeks ago

Location

Remote (EMEA)

Workplace

Remote

Type

Full Time

Salary

USD 140,000 – 180,000

Level

Mid

Role

Backend Engineer

Posted

Jun 24, 2026

Full TimeRemoteMid

The role

Summary

Backend Engineer at PostHog focusing on high-throughput, low-latency feature flag evaluation services. You'll own critical infrastructure handling millions of requests per minute with single-digit millisecond response times, working independently on Rust and Python systems in a distributed, autonomous team environment across European timezones.

What you'll do

Own high-throughput evaluation services: Design, build, and maintain feature flag evaluation services and targeting endpoints that handle millions of requests per minute with sub-10 millisecond latencies. You'll set your own reliability, stability, and performance targets while ensuring zero breaking changes to customer integrations.

Architect distributed systems solutions: Make critical architecture decisions for transitioning feature flag infrastructure from read-heavy to write-heavy models, implement dedicated flag evaluation stores decoupled from the Persons database, and design caching strategies to optimize tail latency across p50/p90/p99 metrics.

Develop and optimize SDKs across multiple languages: Build and maintain client SDKs across JavaScript/TypeScript, Go, Ruby, PHP, Java, .NET, iOS, Android, and Flutter. Ensure feature flags are trivial to implement, obvious to manage, and impossible to forget about while prioritizing developer experience parity.

Implement real-time cohort targeting: Build real-time cohort evaluation capabilities enabling dynamic user targeting based on actions within five-minute windows. This involves implementing complex targeting logic directly at flag-check time rather than relying on delayed membership computation.

Drive reliability and incident response: Carry production pager responsibilities, respond to and resolve critical incidents affecting millions of customers' deployments, implement load shedding and request hedging strategies, and isolate the evaluation path from upstream database failures.

Execute performance optimization projects: Profile and benchmark evaluation engines to identify bottlenecks, port critical components from Python to Rust for performance gains, and continuously reduce p99 latencies while maintaining system correctness and consistency.

Drive AI-first feature flag tooling: Build internal tools enabling AI agents to create, modify, and reason about feature flags programmatically without UI interaction. Dogfood these tools internally to validate UX for agent-driven workflows and ensure backward compatibility.

What we look for

Technical

High-throughput systems designDemonstrated experience building and operating distributed systems handling millions of requests or terabytes of data per minute with deep understanding of caching strategies, tail latency optimization, and failure mode analysis in production environments.

Rust and Python proficiencyProduction-level experience or rapid learning capability in both Rust for high-performance evaluation engines and infrastructure, and Python for backend application development. Must be comfortable context-switching between languages for specific performance requirements.

Database and infrastructure knowledgeUnderstanding of relational databases, query optimization, distributed system concepts, cloud infrastructure provisioning (AWS/GCP/Azure), container orchestration, and the ability to provision and maintain production systems without vendor lock-in considerations.

Systems reliability and observabilityHands-on experience carrying production pagers, debugging production incidents, implementing monitoring and alerting systems, analyzing performance profiles, and using benchmarking tools to identify optimization opportunities in critical path code.

Low-latency system optimizationProven ability to identify and eliminate latency bottlenecks through profiling, caching layer optimization, architectural changes, and algorithmic improvements. Comfortable making tradeoffs between consistency, availability, and latency.

Education

Computer Science fundamentalsStrong foundation in data structures, algorithms, distributed systems theory, and operating systems concepts. Formal CS degree not required but equivalent professional experience demonstrating these competencies essential.

Experience

High-performance backend systems3+ years building backend services where latency and correctness both matter critically. Experience with real-time bidding systems, payment processing platforms, recommendation engines, authentication services, or CDNs valued highly.

Feature flag or CDP platforms (preferred)Familiarity with feature flag infrastructure, customer data platforms, or real-time decision engines demonstrates understanding of evaluation semantics, flag state management, and the compliance/correctness requirements of production feature control systems.

Independent project ownershipTrack record of autonomously owning complete services end-to-end, from architectural design through production deployment. Comfortable driving projects to completion without daily management or design reviews.

Skills

Required skills

RustProduction experience or demonstrated ability to quickly master Rust for performance-critical evaluation engine components and infrastructure optimization.

PythonProficiency in Python for backend application logic, including Django web framework patterns and async Python for high-concurrency scenarios.

Distributed systems designAbility to reason about CAP theorem tradeoffs, consensus algorithms, replication strategies, and failure recovery in multi-node architectures.

Database optimizationSQL query optimization, index design, understanding of relational and columnar data storage patterns, and ability to design schemas for high-throughput evaluation workloads.

Performance profilingHands-on experience with profiling tools (Rust flamegraph, Python cProfile, perf), benchmarking frameworks, and ability to translate profile insights into architectural or algorithmic improvements.

API designExperience designing REST or gRPC APIs that balance throughput with simplicity, including versioning strategies and maintaining backward compatibility for millions of SDK consumers.

Nice to have

JavaScript/TypeScriptFamiliarity with TypeScript enables better understanding of client SDK implementation patterns and cross-platform consistency considerations in feature flag distribution.

Go or JavaExperience with statically-typed, compiled languages provides useful perspective when designing cross-language SDKs and understanding performance tradeoffs in polyglot environments.

Kafka or event streamingBackground with Kafka, Redis Streams, or similar platforms valuable for real-time cohort computation and distributing flag state changes to edge evaluation nodes.

Cloud infrastructure (AWS/GCP/Azure)Hands-on experience provisioning, monitoring, and maintaining production infrastructure on major cloud providers. Familiarity with infrastructure-as-code tooling like Terraform.

Cache layer designExperience implementing and optimizing Redis, Memcached, or custom caching layers to reduce database load and improve evaluation latency.

Message queuesUnderstanding of RabbitMQ, SQS, or other message queue patterns for decoupling components and handling async workloads in evaluation pipelines.

Compensation & benefits

Salary

USD 140,000 – 180,000 (annual)

Stock options

Available

Benefits

Equity (stock options)

Competitive equity package reflecting your role in building a well-funded company valued at $180M+ raised. Equity subject to standard four-year vesting with one-year cliff.

Fully remote work

Work from anywhere within European timezones with no office requirements. PostHog's natively remote infrastructure supports async-first collaboration across distributed teams.

Flexible time off

Unlimited vacation policy demonstrating trust in team autonomy. PostHog's culture emphasizes results over hours, supporting healthy work-life balance.

Maker schedule (meeting-free days)

Tuesdays and Thursdays designated as meeting-free days for uninterrupted heads-down building time. Async-first communication culture (PRs > Issues > Slack) maximizes individual productivity.

Professional development and learning

Support for conferences, training, and skill development. Access to resources for becoming polyglot engineer and deepening systems expertise across multiple languages.

Comprehensive health and wellness benefits

Health insurance coverage including medical, dental, and vision. Mental health and wellness program support reflecting PostHog's employee-first culture.

Home office equipment budget

Stipend for ergonomic desk setup, monitors, keyboards, and other equipment necessary for productive remote work environments.

Co-working space access

Optional monthly co-working space budget in your local timezone for networking opportunities or alternative work environments.

Transparent compensation and equity

PostHog publishes compensation philosophy in public handbook. No hidden salary bands—pay is equitable and based on role and seniority, not negotiation leverage.

Parental and family leave

Generous parental leave and family care policies. PostHog's handbook transparency includes detailed family benefit policies supporting all family structures.

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