Senior Backend Engineer, Mode Mobile

• 5+ years of professional senior backend engineering experience in an agile environment delivering services that support native mobile applications, with hands-on production experience using:
• Go as a primary language: concurrency (goroutines, channels), networking (net, netstack-style packet handling), cgo/gomobile or similar cross-compilation for Android (.aar) and iOS (.framework/XCFramework)
• Python and Node.js for existing services, scripts, and integrations
• PostgreSQL (schema design, migrations, performance) and MongoDB or another document store, plus Redis or similar caching
• AWS: Lambda, S3, RDS, Route 53, IAM, and Docker-based services; familiarity with Terraform/Ansible-managed environments
• REST API design and documentation (OpenAPI/Swagger), authentication (JWT/OAuth), and rate limiting
• GitHub for version control and pull-request based workflows; SOLID, Clean Coding, Testing, and CI/CD (GitHub Actions or similar)
• VPN and networking expertise: working knowledge of WireGuard (peer/key management, configuration generation), Shadowsocks or other proxy/obfuscation protocols, OpenVPN, TCP/IP, DNS, TLS, and how packets flow from a mobile OS tunnel interface through a userspace stack (lwIP, gVisor netstack) to a VPN server
• Experience integrating and operating third-party platforms: Stripe and in-app purchase validation (App Store Server API, Google Play Developer API), analytics and attribution (Amplitude, Firebase, AppsFlyer/Adjust or similar), and observability (Datadog)
• Applied security engineering: secrets management (Vault, AWS Secrets Manager/SSM), encryption of sensitive data at rest, safe cryptographic key generation and storage, dependency and vulnerability scanning, and remediating audit findings
• Agentic AI proficiency: demonstrated day-to-day use of AI agents (e.g., Claude Code, Cursor, GitHub Copilot agents) to write and review infrastructure code, automate runbooks, and investigate incidents, with strong judgment on verifying AI-generated output before it touches production
• You’re a candid and empathetic communicator that is excited to join a startup that enjoys leveling up a company
• You have exceptional organizational and analytical skills leading to confident independent delivery, but know when and how to include others
• You have experience building large-scale systems with some technical leadership skills
• Passionate about Technology and keeping up to date with latest advancements, techniques and best practices
• ​​Accountable: You take ownership of your responsibilities, demonstrating trustworthiness and self-discipline. You are consistent in your work, transparent in your actions, and communicate effectively. You follow through on commitments and strive for continuous improvement
• Action-driven: Identify what is most important, agree on scope, timely execute, and drive the greatest impact. You take initiative, roll up your sleeves, and get things done
• Caring: You genuinely care about yourself and others, our business and craft, our mission and vision, and are passionate in heart and mind. You understand the importance of our team and strive to create a positive, supportive work environment
• Curious: You focus on the ‘why,’ learn and expand your knowledge, explore new ideas, and generally make things better. You're a lifelong learner with a thirst for knowledge and a constant desire to improve
• Thorough: Your work is thoughtful, impactful, timely, accurate, and complete. You pay attention to detail, are meticulous, and ensure quality work and compliance

Desirable

• Mode.Inc is looking for a Senior Backend Engineer with strong Go expertise to join the team taking ownership of our newly acquired VPN product and the additional apps we will be acquiring
• You will help take technical ownership of an existing production VPN following its acquisition by Mode.Inc. Your initial focus will be understanding and stabilizing the existing backend and Go networking engine, closing technical and security gaps, and establishing the engineering foundations needed to evolve the product confidently to a consumer VPN with 10M+ installs, 1,000+ servers in 45+ countries, and users in some of the most restrictive network environments in the world. That engine, a Go library cross-compiled for Android and iOS that embeds a userspace TCP/IP stack and drives the Shadowsocks and WireGuard clients, is the core of the product, and you will be the engineer who understands it, hardens it, and extends it
• We are a user-facing product-led team, and we are looking for someone who is passionate about building private, secure, and resilient systems that people depend on every day
• As an engineer, you’ll be accountable for taking over, stabilizing, and evolving an existing backend: nimbly experimenting with solutions, building high-quality software, and measuring results. You’ll own the account, subscription, and server-selection APIs, the WireGuard peer and configuration pipeline, and the integrations with payments, analytics, and attribution providers
• You’ll establish automated testing, API documentation, and CI/CD where they don’t exist yet, close the security gaps identified during due diligence, and use agentic AI coding tools as a core part of your daily workflow. You’ll work closely with the mobile frontend engineer, DevOps/network engineer, product managers, operations, and several stakeholders to define and execute according to our strategic roadmap to accelerate our future growth
• You are passionate about giving people private, secure, and unrestricted access to the internet. You care about your users and the trust they place in the product
• You enjoy inheriting an existing system, reading unfamiliar code, and reverse-engineering how things work, then making them better with tests, documentation, and refactoring
• You’re an exceptional Go backend engineer with strong networking fundamentals and comfortable across a polyglot backend (Go, Python, Node.js), and you are not afraid to go low-level: raw IP packets, userspace network stacks, proxy and tunnel protocols, and cross-compiling Go for mobile
• You design APIs that mobile clients love: clear contracts, versioning, graceful degradation, and documentation (OpenAPI/Swagger) that the frontend team can build against without asking
• You embrace agentic AI as a force multiplier: you use AI coding agents to plan, implement, test, and review work, and you know when to trust them and when to verify
• You value working closely with Product Management, learning directly from users about what matters to them, and developing solutions that they love
• You care deeply about the impact of your work, and measure success by the value added to users’ lives: connection success rate, API latency and error rates, and subscription conversion and retention
• You’re excited to write high-quality, maintainable, and well-tested code that you deliver. You are eager to find minimal ways to test hypotheses and validate feasibility
• You’re a strong advocate for unit/integration testing and passionate about automated testing and continuously shipping to production
• You are security-minded: secrets management, encryption at rest and in transit, cryptographic key generation and handling, least-privilege access, and user privacy are part of everyday engineering, not an afterthought
• First 30 days
• Understand the existing backend and Go networking engine
• Map critical services, dependencies and data flows
• Establish local development/debugging workflow
• Identify highest-risk reliability/security issues
• Contribute to 100% uptime
• 60 days
• Own meaningful production changes
• Improve test coverage around critical paths
• Close priority technical gaps from due diligence
• Establish better observability/documentation where needed
• 90 days
• Independently own backend/VPN-engine initiatives
• Improve connection reliability / API reliability
• Reduce operational/manual pain
• Contribute confidently to product and technical roadmap
• Contribute to Uptime at world class market levels for similar products