AI Engineer

Arena; São Paulo; On-site; BRL 180,000 - 240,000; Full time

Benefits offered by this job

4 weeks paid time-off

Learning & Development budget

Competitive salary package

Job summary

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

Join a fast-growing global team, develop production-ready AI pipelines, and contribute to products used by millions of users across countries.

Qualifications

• 2+ years of experience in AI Engineering or similar technical role.
• Strong Python programming skills and experience building production software.
• Hands-on experience with LLMs, Generative AI, and AI APIs.
• Experience with RAG, embeddings, vector databases, agents, or tool calling.
• Understanding of AI evaluation, prompt engineering, model behavior, and production trade-offs.
• Experience with APIs, cloud infrastructure, and distributed systems.
• Fluent English.

Responsibilities

• 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 improve AI performance.
• Build experiments and prototypes, then scale successful approaches to production.
• Collaborate with Product and Engineering to translate problems into AI solutions.

Skills

Python

LLMs

AI APIs

Production software

Problem solving

English fluency

Tools

LangChain

LangGraph

Node.js

TypeScript

AWS

WebSockets

GraphQL

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.

We also have some sweet perks like:

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.