Overview

Most everyday applications like email, messaging platforms, calendars, and note tools still function as if artificial intelligence does not exist. Expecting everyday people to craft intricate prompts just to handle simple logistics is flawed. At Bjak, we are building proactive, AI-native products that effortlessly streamline errands, discussions, and personal workflows without placing the burden of prompting on the user. Our primary application centers on an agent-first mobile communication ecosystem designed to reduce coordination friction and elevate daily collaboration. To power these experiences, we are seeking a Machine Learning Engineer focused on Ranking and Retrieval to join our worldwide, fully remote team.

Key Responsibilities

In this role, you will take complete ownership of core algorithmic systems from initial concept and training through to production deployment. Key duties include the following areas

Model Development: Build and iterate on machine learning models specialized in classification, candidate retrieval, ranking, and personalization.
System Architecture: Design low-latency semantic search pipelines and vector retrieval architectures capable of scaling across millions of daily interactions.
Evaluation Frameworks: Create rigorous offline and online evaluation protocols to benchmark relevance, latency, and model quality against real user outcomes.
Production Engineering: Partner closely with application teams to deploy performant inference services that integrate smoothly with mobile clients.
Continuous Optimization: Refine feature stores, training data generation, and loss functions to boost recommendation accuracy over time.

Requirements

We value pragmatic problem solvers who care deeply about shipping functional systems rather than theoretical exercises. Ideal experience includes

Solid background in developing and supporting production machine learning workflows, especially in ranking, retrieval, or recommendation systems.
Deep familiarity with modern search techniques, vector databases, bi-encoders, cross-encoders, and collaborative filtering.
Strong coding skills in Python alongside practical experience with frameworks such as PyTorch or TensorFlow.
Working knowledge of high-throughput inference optimization, model quantization, and caching strategies.
Demonstrated ability to communicate clearly and operate independently within an asynchronous, global remote setup.

What You'll Gain

Working with us offers direct influence over how the next generation of mobile software takes shape. Team members benefit from several key advantages

Complete Flexibility: Work on a fully remote basis from anywhere in the world with autonomy over your schedule.
Tangible Impact: Ship models directly to production that transform how real people manage their daily communication.
Innovative Environment: Collaborate with a fast-moving engineering crew focused on building practical, agentic AI products from the ground up.
Technical Growth: Tackle complex scaling, low-latency inference, and state-of-the-art retrieval challenges at scale.