Application & Integration Coding
Practice the APIs, customer data, webhooks, state, and reliability problems that appear in hands-on FDE interviews.
CRM Billing Synchronizer
Build an accurate, efficient sync across two changing systems. The CRM is the source of truth.
Webhook Order Processor
Project duplicate and out-of-order webhook deliveries into reliable order state.
Resumable Customer Backfill
Copy a paginated customer dataset into a warehouse without losing progress or duplicating rows.
Support Agent Productivity
Turn an audit trail of ticket activity into trustworthy daily agent metrics.
Debug a Broken Customer Sync
Trace and repair a small integration whose pagination, retries, and writes fail in different ways.
Concurrent Inventory Reservation
Reserve limited stock safely when another checkout can modify inventory between your read and write.
Rate-Limited Customer Enrichment
Enrich paginated CRM customers without dropping partial progress or hammering a constrained provider.
Queue Consumer with Poison Messages
Process an at-least-once payment queue without duplicate ledger effects or endless retry loops.
Normalize Messy CRM Records
Convert inconsistent records from multiple CRM exports into one predictable schema.
Validate JSON Tool-Call Arguments
Validate untrusted model-generated arguments before a tool can touch customer systems.
Chunk Documents with Overlap
Split text into overlapping word windows without producing duplicate trailing chunks.
Filter RAG Chunks by User Permissions
Prevent cross-tenant and role-based data leakage before constructing a model prompt.
Pack a Retrieval Context Window
Select ranked chunks under a token budget while preserving retrieval order.
Retry Failed API Calls with Backoff
Retry transient integration failures without retrying permanent errors or waiting in tests.
Build an LRU Cache
Implement predictable least-recently-used eviction for a small in-memory cache.
Detect Tenant Cost Anomalies
Flag meaningful cost spikes without alerting on empty or tiny historical baselines.
Detect SLA Breaches
Evaluate resolved and still-open tickets against priority-specific response targets.
Reconstruct an Incident Timeline
Correlate unordered events from multiple services into deterministic request timelines.