AI Engineer

Arenaim; São Paulo; On-site; BRL 120,000 - 190,000; Full time

Benefits offered by this job

Global team

Competitive pay

4 weeks PTO

Learning budget

Impact on products

Job summary

Arena is seeking an AI Engineer to build and scale AI-powered experiences across Arena and MyAvatar.AI. You will work closely with Engineering, Product, and AI-focused teams to design, implement, evaluate, and improve AI systems powering conversational, voice, and multimodal experiences.

The role emphasizes strong Python, hands-on LLMs and AI APIs, with experience in RAG, embeddings, and tool calling. You will translate business problems into practical AI solutions and improve production

Qualifications

• 2+ years in AI/ML or software engineering focusing on AI systems.
• Strong Python programming and production software experience.
• Hands-on with LLMs, Generative AI and AI APIs.
• Experience with RAG, embeddings, vector databases, agents or tool calling.
• Solid understanding of AI evaluation, prompt engineering and trade-offs.
• Experience with APIs, cloud infra and distributed systems.
• Can translate problems into practical AI solutions and move quickly.

Responsibilities

• Build and integrate AI-powered features into production apps.
• Develop LLM-powered apps using APIs, agents and tool calling.
• Design and improve AI pipelines for conversational and multimodal experiences.
• Evaluate model quality, latency, reliability, and cost.
• Build experiments, turn results into scalable production systems.
• Collaborate with Product and Engineering to solve business problems with AI.

Skills

Python

LLMs & Generative AI

AI APIs

RAG

Embeddings

Vector databases

Agents & tool calling

Prompt engineering

Model evaluation

Production systems

APIs & cloud infra

Distributed systems

Problem solving

English fluency

Tools

LangChain

Node.js

TypeScript

AWS

GraphQL

MongoDB

PostgreSQL

WebSockets

Job description

About Arena

Arena is a Series A company backed by top-tier investors such as CRV, Redpoint and Craft Ventures. Arena offers a unique work environment and the chance to collaborate with diverse teammates across multiple countries, with a culture of ownership (autonomy, growth, and responsibility). We are a startup created in Silicon Valley with a mission to build communities for creators, publishers and brands with the power of AI. Companies using Arena include Disney, Reuters, Fox, Red Bull and NFL. We have +2,000 customers in 150 countries, with +50M users having conversations on Arena every month and engaging with our AI Agents. Arena is also expanding its AI product portfolio with MyAvatar.AI, a multimodal platform that enables users to create intelligent, personalized AI avatars through voice, video, and conversational interfaces. Sometimes you're stuck in a job that doesn't make sense, building AI features that never make it into production. If you enjoy turning cutting-edge AI into real products, solving complex problems, and seeing your work used by millions of users - then Arena is the company you're looking for.

About the Role

We're looking for an AI Engineer to build and scale AI-powered experiences across Arena and MyAvatar.AI. You'll work closely with Engineering, Product, and other AI-focused teams to design, implement, evaluate, and improve AI systems that power conversational, voice, and multimodal experiences.

What you will be doing

• Build and integrate AI-powered features and services into production applications.
• Develop LLM-powered applications using APIs, agents, RAG, tool calling, and structured outputs.
• Design and improve AI pipelines for conversational, voice, and multimodal experiences.
• Evaluate model quality, reliability, latency, and cost, and continuously improve AI performance.
• Build experiments and prototypes, then turn successful approaches into scalable production systems.
• Collaborate with Product and Engineering to translate business and user problems into practical AI solutions.

Must-Have Experience

• 2+ years of experience in AI Engineering, Machine Learning Engineering, Software Engineering, or a similar technical role.
• Strong Python programming skills and experience building production software.
• Hands-on experience with LLMs, Generative AI, and AI APIs.
• Experience building applications with RAG, embeddings, vector databases, agents, or tool calling.
• Strong understanding of AI evaluation, prompt engineering, model behavior, and production trade-offs.
• Experience working with APIs, cloud infrastructure, and distributed systems.
• Strong problem-solving skills and ability to move quickly from prototype to production.
• Fluent English.

Nice-to-Have Experience

• Experience with LangChain and LangGraph for building LLM applications, agents, and AI workflows.
• Experience with Node.js and TypeScript or other backend languages.
• Experience with AWS, serverless architectures, and cloud-native applications.
• Experience with real-time systems, WebSockets, GraphQL, or APIs.
• Experience with MongoDB, PostgreSQL, Redis, or other distributed data systems.

Perks

• Be a part of the team in Silicon Valley and join a global team.
• A team of exceptional engineers leading the cutting-edge AI Agents.
• Competitive salary package & benefits.
• 4 weeks of paid time-off.
• Learning and Development budget.
• Key moment to join Arena in terms of growth and opportunities.
• Ability to put your stamp on real-world AI applications that serve millions of users.
• Fast-learning environment, entrepreneurial and strong team spirit.
• Multiple nationalities: cosmopolite & multi-cultural mindset.
• Our people matter, work-life balance is important at Arena.