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Machine Learning Engineer
MailerLite
Remote
Full-time
$62,400 -
$90,800
About MailerLite
MailerLite is one of the fastest-growing email marketing services. We help more than 1 million businesses around the world stay in touch with their customers. Today, we are a team of more than 170 dreamers, adventurers, and world travelers passionate about what we do and what we believe in. And we are ready for another talented person to join the party.
About the Role
We’re looking for a Machine Learning Engineer to help us build the intelligence layer behind our products - turning the behavioral data of over a million businesses into predictions and actions that help our customers reach the right people, at the right time, on the right channel, without needing a full marketing team. You’ll work across the full ML spectrum: classical predictive models on large-scale behavioral data and applied LLM work, including fine-tuning models on our own data to power a goal-driven assistant.
We’re betting the next phase of MailerLite on ML, and this is one of the first hires to make it real. The data’s already here. The team is still taking shape — and you’ll play a key role in defining it. We're looking for someone who's excited to help build what's next.
We’re betting the next phase of MailerLite on ML, and this is one of the first hires to make it real. The data’s already here. The team is still taking shape — and you’ll play a key role in defining it. We're looking for someone who's excited to help build what's next.
Qualifications
3+ years of experience building and shipping ML models in production (not just prototypes).
Strong applied ML fundamentals: feature engineering, calibration, leakage avoidance, and honest evaluation - especially on imbalanced and time-series problems.
Hands-on LLM fine-tuning experience (supervised fine-tuning at minimum).
Fluency in Python and the modern ML stack (e.g. scikit-learn, gradient boosting, pandas/Polars, PyTorch).
Comfort writing performant SQL over large datasets and working with event/columnar stores and relational databases.
Experience designing training and inference pipelines and the orchestration around them.
A strong sense of ownership and the ability to work autonomously in a remote, async team.
Clear written communication.
At least 4 hours overlap required with CET time zone.
Bonus skills
Preference optimization (DPO/RLHF-style) or reinforcement learning experience.
Experience with multi-GPU / distributed training.
Structured / constrained generation (function calling, schema-constrained output).
Experience building agentic, tool-using systems against real APIs.
Anomaly detection, uplift/causal modeling, or recommender/segmentation work.
Background in marketing, growth, deliverability, or other behavioral-data domains.
Strong applied ML fundamentals: feature engineering, calibration, leakage avoidance, and honest evaluation - especially on imbalanced and time-series problems.
Hands-on LLM fine-tuning experience (supervised fine-tuning at minimum).
Fluency in Python and the modern ML stack (e.g. scikit-learn, gradient boosting, pandas/Polars, PyTorch).
Comfort writing performant SQL over large datasets and working with event/columnar stores and relational databases.
Experience designing training and inference pipelines and the orchestration around them.
A strong sense of ownership and the ability to work autonomously in a remote, async team.
Clear written communication.
At least 4 hours overlap required with CET time zone.
Bonus skills
Preference optimization (DPO/RLHF-style) or reinforcement learning experience.
Experience with multi-GPU / distributed training.
Structured / constrained generation (function calling, schema-constrained output).
Experience building agentic, tool-using systems against real APIs.
Anomaly detection, uplift/causal modeling, or recommender/segmentation work.
Background in marketing, growth, deliverability, or other behavioral-data domains.
Responsibilities
Build and ship predictive models on large-scale behavioral and event data - predicting engagement, finding the best time and audience for each message, scoring list health, and discovering customer segments.
Fine-tune LLMs on our own data and outcomes to power a goal-driven assistant that recommends and takes action on a customer's behalf.
Design and own the training and inference pipelines behind these models - data prep, training, evaluation, and serving.
Build evaluation harnesses that prove a model is genuinely better before it ships - measuring real-world lift, not just offline metrics.
Enforce reliable, structured model outputs so predictions and actions can be trusted in production.
Collaborate with product and engineering teams who consume your models as shared infrastructure.
Fine-tune LLMs on our own data and outcomes to power a goal-driven assistant that recommends and takes action on a customer's behalf.
Design and own the training and inference pipelines behind these models - data prep, training, evaluation, and serving.
Build evaluation harnesses that prove a model is genuinely better before it ships - measuring real-world lift, not just offline metrics.
Enforce reliable, structured model outputs so predictions and actions can be trusted in production.
Collaborate with product and engineering teams who consume your models as shared infrastructure.
Benefits
Remote-first culture: Our team works remotely from around the world.
International health insurance: Provided with coverage in most countries, with a monthly payout available in select countries where coverage is limited.
Company-paid retreats: Once a year, we gather for a week in a beautiful location to work, learn, and have fun together.
31 days of vacation (including public holidays): We encourage you to unplug and recharge!
12 paid sick days: For your physical and mental well-being, no doctor's note required. Parents can use them to care for their sick children.
4 creative days: One paid day off per quarter to do something creative and fun.
12 parental days: Enjoy one paid day off each month to treasure time with your children.
Parental leave: 100% paid leave when welcoming a new child through birth (3 months maternity, 1 month paternity) or adoption.
Parenting budget of $1000: A $1000 special gift to celebrate the arrival of your little one, whether through childbirth or adoption.
Joy Budget: Annual allowance to spend on what brings you joy, starting at $1,000 per year and increasing over time.
MacBook and other tools: That help you to do your job efficiently.
International health insurance: Provided with coverage in most countries, with a monthly payout available in select countries where coverage is limited.
Company-paid retreats: Once a year, we gather for a week in a beautiful location to work, learn, and have fun together.
31 days of vacation (including public holidays): We encourage you to unplug and recharge!
12 paid sick days: For your physical and mental well-being, no doctor's note required. Parents can use them to care for their sick children.
4 creative days: One paid day off per quarter to do something creative and fun.
12 parental days: Enjoy one paid day off each month to treasure time with your children.
Parental leave: 100% paid leave when welcoming a new child through birth (3 months maternity, 1 month paternity) or adoption.
Parenting budget of $1000: A $1000 special gift to celebrate the arrival of your little one, whether through childbirth or adoption.
Joy Budget: Annual allowance to spend on what brings you joy, starting at $1,000 per year and increasing over time.
MacBook and other tools: That help you to do your job efficiently.
