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Senior Python Engineer / Lead Developer

Cyfrin

cyfrin.io

GB

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Job type

Work type

Experience

Position Overview

We're seeking an exceptional Senior Python Engineer to take technical leadership of a complex, production-grade codebase. This role involves architecting and developing sophisticated systems that combine AI/LLM integration, code analysis, and security tooling. You'll be responsible for architectural decisions, feature development, team mentorship, and maintaining the highest standards of code quality.

Location: Remote

Experience Level: Senior (5+ years)

Commitment: Full-time

Core Responsibilities

Technical Leadership

  • Make critical decisions about system architecture, design patterns, and technology choices

  • Establish and enforce coding standards, review practices, and quality benchmarks

  • Define and prioritize technical initiatives aligned with product goals

  • Lead architectural discussions and drive consensus on complex technical decisions

  • Ensure system performance and scalability for production workloads

Feature Development

  • Design and implement core system components using modular, extensible architectures

  • Build and maintain integrations with external APIs and services (LLM providers, databases, etc.)

  • Develop analysis engines and processing pipelines for complex data workflows

  • Implement testing frameworks and validation systems

  • Optimize critical code paths and system bottlenecks

Team Collaboration & Mentorship

  • Review pull requests and provide constructive technical feedback

  • Mentor junior and mid-level engineers in best practices and technical growth

  • Maintain comprehensive technical documentation and architectural diagrams

  • Conduct technical presentations and knowledge transfer sessions

  • Collaborate across functions with stakeholders and team members

Technical Innovation

  • Stay current with advances in Python ecosystem, AI/ML technologies, and relevant domains

  • Evaluate and integrate new libraries, frameworks, and tools

  • Research and prototype solutions to complex technical challenges

  • Contribute to technical strategy and long-term planning

Required Technical Skills

Python Expertise (Required)

  • 5+ years of professional Python development with advanced proficiency in:

    • Async/await patterns and concurrent programming

    • Type hints and Pydantic for data validation

    • Decorators, metaclasses, and advanced language features

    • Modern package management (uv, pip, poetry)

    • Testing frameworks (pytest, mocks, fixtures, test-driven development)

  • Software Architecture: Experience designing modular, plugin-based systems with clean abstractions

  • API Design: Creating intuitive interfaces and maintainable code structures

  • Performance: Profiling, optimization, and handling large-scale data processing

  • Version Control: Git workflows, code review practices, and collaborative development

LLM & AI Integration (Preferred)

  • LLM APIs: Hands-on experience with OpenAI, Anthropic, or similar providers including:

    • Function/tool calling and structured outputs

    • Prompt engineering and optimization

    • Session management and conversation state

    • Token tracking and cost optimization

  • RAG Systems (Nice to have): Experience with vector databases (ChromaDB, Pinecone, Weaviate), embeddings, semantic search, LlamaIndex or LangChain

  • AI/ML Concepts: Understanding of temperature, sampling, context windows, and model behavior

Code Analysis & Parsing

  • AST & Static Analysis: Experience with abstract syntax trees, code parsing, and program analysis

  • Pattern Matching: Regex, semantic search, and code query techniques

  • Control Flow: Understanding of call graphs, data flow, and execution path analysis

Smart Contracts (Preferred)

  • Solidity and/or Rust: Ability to read and understand smart contract code

  • Blockchain Fundamentals: Knowledge of EVM, transactions, gas mechanics, and contract execution patterns

  • Security Awareness: Familiarity with common vulnerability patterns (reentrancy, access control, etc.)

  • Tooling: Experience with Foundry, Hardhat, Anchor, or similar development frameworks

Additional Skills

  • CLI Development: Building command-line tools (Typer, Click, argparse)

  • Web Frameworks (Nice to have): Flask, FastAPI for APIs and web interfaces

  • DevOps Basics: CI/CD, Docker, GitHub Actions

  • Data Storage: Working with JSON, databases, and caching systems

Software Development Best Practices

  • Clean Code: SOLID principles, design patterns, and writing maintainable, extensible code

  • Documentation: Clear technical documentation, architecture decision records (ADRs), and API documentation

  • Testing Strategy: Comprehensive testing approaches including unit, integration, and end-to-end tests

  • Code Review: Effective review practices with constructive, actionable feedback

  • Agile Development: Experience with iterative development and continuous improvement

  • Security Mindset: Awareness of common security vulnerabilities and defensive programming practices

Preferred Qualifications

Experience

  • 5+ years of professional Python development

  • 2+ years in a technical leadership or senior engineering role

  • Experience building AI/LLM-powered applications in production

  • Background in security, static analysis, or developer tools

  • Experience with smart contracts (Solidity, Rust) or blockchain technologies (strong plus)

  • Active open-source contributions (strong plus)

Technical Accomplishments

  • Built and deployed production systems with complex workflows

  • Designed and implemented modular, plugin-based architectures

  • Experience with large-scale data processing or analysis systems

  • Technical writing, blog posts, or conference presentations (plus)

Posted 2 months ago