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Refund Service Low-Level Design: Partial Refunds, Ledger Entries, and Gateway Callbacks

⏱ 5 min read Refund Service Low-Level Design The refund service is responsible for calculating how much to return to a buyer, executing the […] Read article

Apr 17, 2026 System Design

Image Recognition Service Low-Level Design: Model Serving, Batch Inference, and Confidence Thresholds

⏱ 5 min read Image Recognition Service System Design Overview An image recognition service accepts raw image input, runs it through one or more […] Read article

Apr 17, 2026 System Design

Content Classifier Low-Level Design: Multi-Label Classification, Ensemble Models, and Human Review

⏱ 5 min read Content Classifier System Design Overview A content classifier assigns one or more category labels to user-generated content: text posts, images, […] Read article

Apr 17, 2026 System Design

Risk Scoring Service Low-Level Design: Multi-Signal Aggregation, Model Ensemble, and Score Explanation

⏱ 6 min read Requirements and Constraints A risk scoring service aggregates signals from multiple data sources, runs them through an ensemble of models, […] Read article

Apr 17, 2026 System Design

IoT Data Pipeline Low-Level Design: Device Ingestion, Stream Processing, and Time-Series Storage

⏱ 6 min read Requirements and Constraints An IoT data pipeline ingests telemetry from potentially millions of connected devices, processes and enriches the stream, […] Read article

Apr 17, 2026 System Design

Device Registry Low-Level Design: Provisioning, Metadata Store, and Fleet Management

⏱ 6 min read Requirements and Constraints A device registry is the source of truth for IoT device identity, credentials, configuration, and metadata. It […] Read article

Apr 17, 2026 System Design

Telemetry Collector Low-Level Design: Metric Scraping, Aggregation, and Forwarding Pipeline

⏱ 6 min read Requirements and Constraints A telemetry collector receives metrics from services and infrastructure components, aggregates them locally to reduce cardinality and […] Read article

Apr 17, 2026 System Design

Fulfillment Service Low-Level Design: Order Splitting, Warehouse Routing, and SLA Tracking

⏱ 5 min read Requirements and Constraints A fulfillment service sits between order management and warehouse execution. It receives orders, decides which warehouse(s) should […] Read article

Apr 17, 2026 System Design

Shipping Tracker Low-Level Design: Carrier Integration, Event Normalization, and ETA Prediction

⏱ 5 min read Requirements and Constraints A shipping tracker aggregates parcel status from multiple carriers (FedEx, UPS, USPS, DHL, regional last-mile), normalizes heterogeneous […] Read article

Apr 17, 2026 System Design

Experiment Platform Low-Level Design: Multi-Armed Bandit, Holdout Groups, and Guardrail Metrics

⏱ 7 min read Requirements and Constraints A full-featured experiment platform extends simple A/B testing to support adaptive allocation (multi-armed bandits), holdout groups, guardrail […] Read article

Apr 17, 2026 System Design