Applied AI Engineer

About Everfit

Everfit is one of the fastest growing fitness coaching platforms in the world. We power more than 320,000 coaches across the globe with an all-in-one AI-powered platform to run and grow their businesses. In 6 years, we have become one of the leaders of the health and wellness B2B SaaS category in the US and around the world! We are at an inflection point. We are focusing our efforts to capture more of the $5.1 trillion health and fitness market by going direct to consumers. Our vision is to become the operating system for personal health, where anyone can plug in a coach, or multiple coaches, to reach their wellness goals faster, optimize their human potential, and extend their longevity.

Our team spans from San Francisco to Vietnam, with senior leaders who have built and scaled products at Netflix, Apple, Meta, Nike, Hulu, Uber, Amazon, Hypebeast, and Quibi. We are building the next unicorn to come out of Vietnam, and we are looking for a confident leader who can help us get there.

Position Overview:

As an Applied AI Engineer at Everfit, you'll work at the intersection of backend engineering and applied AI, building the scalable systems and AI-powered experiences that shape the future of fitness coaching for coaches and their clients around the world.

This is not a Backend role with AI sprinkled on top. Expect roughly 70% of your work on LLM-powered systems (agent workflows, RAG, tool calling, evals) and 30% on the core backend services that power them.

Your impact:

What you'll build

• Durable, long-running AI workflows on Temporal: scheduled jobs and multi-step agent processes that survive restarts, retries, and partial failures.
• Reliable AI pipelines with validation, retries, fallbacks, guardrails, and observability.
• Systems designed around AI-specific constraints: latency, token cost, model failures, quality.
• Production integrations with OpenAI and Anthropic models.
• The path from experiment to production: take a validated AI capability from the AI team and ship it as a service with clear reliability, cost, and quality characteristics.
• Evals and monitoring that define how AI features are measured, and catch regressions before users do.

How you'll work

• Scalable backend services in [protected info], with system architecture, technical design, and code review across Everfit's backend.
• Rapid experiments with emerging AI tech, turning the successful ones into production solutions.
• Day-to-day with Product Managers, AI Engineers, and QA, from technical discovery through delivery.
• Investigating production issues and improving AI workflows from real user feedback.
• Helping the broader engineering org adopt AI-native development practices.

• 4+ years of professional backend engineering experience.
• Comfortable communicating in English and working with an international team.
• Strong programming experience (preferably [protected info] / TypeScript / Python) and backend architecture. Our core backend is [protected info] and our AI services are Python/FastAPI; you'll work mainly in Node but should be comfortable crossing into Python when the work lives there.
• Solid understanding of REST APIs, microservices, distributed systems, databases, and scalable system design.
• Strong experience with databases such as MongoDB, PostgreSQL, and Redis.
• You have shipped at least one LLM-powered feature to production for real users, working directly with OpenAI or Anthropic APIs, and can talk concretely about its failure modes, evals, latency, and cost.
• You already use AI coding tools (Claude Code, Codex) daily, and you review what they produce with judgment about architecture, security, and edge cases.
• Comfortable experimenting with new AI tools and technologies and turning successful experiments into production solutions.
• Curious, proactive, and excited about how AI can fundamentally change software development and product experiences.

[Nice to have]

• Experience with Python / FastAPI or AI-focused backend development.
• Experience building production LLM features, RAG pipelines, or agentic systems.
• Familiarity with the stack we run in production: Pydantic/LangGraph, Qdrant for vector search, Langfuse for LLM observability, and MCP.
• Experience with AWS, Docker, message queues, or cloud-native architecture.
• Experience improving engineering productivity through AI, with measurable impact.
• Experience working with health, fitness, wellness, personalization, or recommendation systems.
• Open-source contributions or personal projects involving AI.

Compensation & Benefits:

• Full social insurance coverage and premium healthcare benefits.
• Competitive salary with 13th-month pay and performance bonus.
• Paid leave - vacation, sick leave, and maternity leave

Build Your Career with Impact:

• Be part of a mission-driven company that's transforming human potential.
• Empower over 300,000+ coaches in more than 200 countries - including Olympic athletes, military trainers, rehab specialists, and celebrity coaches.
• Make a global impact while building a meaningful, purpose-driven career.
• Continuous training, mentoring.
• 1-2 performance reviews annually.

Work Environment:

• English-speaking, international environment promoting open communication and collaboration.
• Work alongside world-class talent from companies like Apple, Meta, Uber, Patreon, and Nike, united by a shared passion for impact and excellence.
• International team for global career growth.
• State-of-the-art equipment provided.
• Beautiful working environment near Danang's city center (Dragon Bridge) and Hanoi office.

Health & Wellness:

• PVI health insurance program and annual health check-ups.
• Active sports clubs (football, badminton, pickleball) and company retreats.
• A modern pantry designed for relaxation and social connection.
• Monthly wellness and learning workshops to recharge and grow.