Define the RL formulation
Specify what constitutes state, actions and the reward in your recommendation context; for example, user features as state and ranked items as actions.
Learn an epsilon-greedy policy. Judge exploration versus exploitation.
This project introduces a production-minded view of reinforcement learning for recommendations and provides a compact baseline: a simulation of an epsilon-greedy multi-armed bandit. Key practical issues include defining state and action spaces, designing a reward signal that aligns with business goals, and measuring stability across random seeds and edge cases.
Learning concept · Not a validated service
This project introduces a production-minded view of reinforcement learning for recommendations and provides a compact baseline: a simulation of an epsilon-greedy multi-armed bandit. Key practical issues include defining state and action spaces, designing a reward signal that aligns with business goals, and measuring stability across random seeds and edge cases.
A proposed use-case is an online product ranking pilot that A/B tests simple bandit policies to increase click or purchase rates while maintaining a manual-override safety path; the supplied starter does not implement a live recommendation pipeline.
Specify what constitutes state, actions and the reward in your recommendation context; for example, user features as state and ranked items as actions.
Simulate an epsilon-greedy or UCB bandit on synthetic or logged click data to validate exploration behaviour and learning speed.
Track cumulative reward, per-action selection counts, and stability across random seeds; also measure business metrics such as conversion uplift.
Add logging, online safety constraints, and a service wrapper; monitor drift, latency and offline-to-online replay agreement.
The supplied starter simulates a 4-armed bandit using an epsilon-greedy strategy with fixed true reward rates. It initialises estimated values and action counts, chooses actions by epsilon exploration or greedy exploitation, samples binary rewards, updates sample-average estimates, and prints action counts, estimated rates and total reward.
for step in range(1, 2001):
if rng.random() < epsilon:
action = rng.integers(len(true_reward_rates))
else:
action = int(np.argmax(estimated_values))
reward = 1 if rng.random() < true_reward_rates[action] else 0
action_counts[action] += 1
total_reward += reward
estimated_values[action] += (reward - estimated_values[action]) / action_counts[action]The code is a contextual-agnostic bandit simulation on synthetic Bernoulli arms and does not use recommendation data, user or item state, a catalog, session modelling, or a production policy wrapper. It is not a full reinforcement-learning recommender (no trajectories, no state transitions, no logged user interactions).
A proposed extension is to replay real logged clicks as bandit feedback, add contextual features (user/session/item), and compare epsilon-greedy with contextual bandit or policy-gradient agents under safe-exploration constraints.
This is a potential application pathway, not a delivered product. The supplied starter does not implement this service or validate it with real users.
Networkers Home runs this topic inside its AI Engineer Course, with placement support and hands-on labs.