# Kingsley Onoh — Systems Architect > I build the backend systems that companies depend on. Pricing engines, data pipelines, and automation that runs without someone watching it. ## About - Systems Architect specializing in pricing engines, data pipelines, and backend automation - Works with founders and engineering teams on architecture decisions and system design - Contact: https://www.kingsleyonoh.com/contact ## Case Studies (Foundry) - [Client Management Portal](https://www.kingsleyonoh.com/foundry/client-management-portal): Client Management Portal is an internal operating system for small agencies and solo delivery teams… - [Explainable Dispatch Optimization Engine](https://www.kingsleyonoh.com/foundry/explainable-dispatch-optimization-engine): Explainable Dispatch Optimization Engine is a dispatch control system for field-service operators… - [Trade Compliance Classification Engine](https://www.kingsleyonoh.com/foundry/trade-compliance-classification-engine): Trade Compliance Classification Engine is a classification workflow for import-heavy operators that… - [Peak Demand Planning Engine](https://www.kingsleyonoh.com/foundry/peak-demand-planning-engine): Peak Demand Planning Engine is a planning tool for facility managers and energy teams that turns… - [Inventory Allocation Simulator](https://www.kingsleyonoh.com/foundry/inventory-allocation-simulator): Inventory Allocation Simulator is a planning console for distributors, retailers, and supply-chain… - [Returns & Claims Orchestration Engine](https://www.kingsleyonoh.com/foundry/returns-claims-orchestration-engine): Returns & Claims Orchestration Engine is a logistics operations console for e-commerce teams that… - [Compliance Document Substrate](https://www.kingsleyonoh.com/foundry/compliance-document-substrate): Klevar Docs is an internal document issuance and audit system for a multi-entity company. It gives… - [Delivery Tracking Gateway](https://www.kingsleyonoh.com/foundry/delivery-tracking-gateway): Delivery Tracking Gateway is a parcel tracking API for logistics and operations teams that need… - [Dispute Resolution Workbench](https://www.kingsleyonoh.com/foundry/dispute-resolution-workbench): Dispute Resolution Workbench is a finance exception queue for operators who need invoice… - [SLA Penalty Settlement Engine](https://www.kingsleyonoh.com/foundry/sla-penalty-settlement-engine): SLA Penalty Settlement Engine is a vendor-credit recovery system for procurement and finance teams… - [Vendor Performance Intelligence Engine](https://www.kingsleyonoh.com/foundry/vendor-performance-intelligence-engine): Vendor Performance Intelligence Engine is a supplier risk monitoring system for procurement leaders… - [Contract Lifecycle Engine](https://www.kingsleyonoh.com/foundry/contract-lifecycle-engine): Contract Lifecycle Engine is a contract and obligation tracking API for legal-ops, procurement, and… - [Invoice Reconciliation Engine](https://www.kingsleyonoh.com/foundry/invoice-reconciliation-engine): Invoice Reconciliation Engine is an accounts payable control system for finance teams that need… - [Sensor Telemetry Engine](https://www.kingsleyonoh.com/foundry/sensor-telemetry-engine): Sensor Telemetry Engine is an IoT monitoring backend for operations teams that need high-volume… - [Subscription Lifecycle Engine](https://www.kingsleyonoh.com/foundry/subscription-lifecycle-engine): Subscription Lifecycle Engine is a payment recovery and subscription-state service for SaaS… - [Clinical Scheduling Engine](https://www.kingsleyonoh.com/foundry/clinical-scheduling-engine): Clinical Scheduling Engine is a scheduling service for clinic operators that computes bookable… - [Financial Compliance Ledger](https://www.kingsleyonoh.com/foundry/financial-compliance-ledger): Financial Compliance Ledger is an append-only audit record for finance and compliance teams that… - [Webhook Ingestion Engine](https://www.kingsleyonoh.com/foundry/webhook-ingestion-engine): Webhook Ingestion Engine is a shared webhook intake service for engineering teams that need signed… - [Workflow Automation Engine](https://www.kingsleyonoh.com/foundry/workflow-automation-engine): Workflow Automation Engine is a self-hosted workflow service for engineering teams that need… - [Event-Driven Notification Hub](https://www.kingsleyonoh.com/foundry/event-driven-notification-hub): Event-Driven Notification Hub is a shared delivery service for engineering teams that need… - [Multi-Agent RAG Platform](https://www.kingsleyonoh.com/foundry/multi-agent-rag-platform): Multi-Agent RAG Platform is an AI backend for document-heavy teams that need search and chat over… - [Transaction Reconciliation Engine](https://www.kingsleyonoh.com/foundry/transaction-reconciliation-engine-foundry): Transaction Reconciliation Engine is a backend for finance and accounting teams that need Stripe,… - [Centralized Property Intelligence Hub](https://www.kingsleyonoh.com/foundry/centralized-property-intelligence): Centralized Property Intelligence Hub is a property data layer for product and AI teams that need… - [Idealo Price Optimization Platform](https://www.kingsleyonoh.com/foundry/idealo-price-optimization-platform): Idealo Price Optimization Platform is a marketplace pricing tool for e-commerce sellers that need… - [NBA Scenario Engine](https://www.kingsleyonoh.com/foundry/nba-scenario-engine): NBA Scenario Engine is a player-prop scenario tool for bettors and analysts who need injury news… - [Solar Pricing Engine](https://www.kingsleyonoh.com/foundry/solar-pricing-engine): Solar Pricing Engine is a pricing pipeline for e-commerce operators that need supplier price lists,… ## Technical Writing (Journal) - [JSONB Was Fine. The Side Effects Needed a State Boundary.](https://www.kingsleyonoh.com/journal/client-management-portal-jsonb-state-boundary): What should happen when a checklist item sends a client message? In this portal, that question… - [Why I made OR-Tools prove it was better than the deterministic dispatcher](https://www.kingsleyonoh.com/journal/explainable-dispatch-optimization-engine-deterministic-solver-boundary): Dispatch optimization needs a lower bound before it needs a clever objective. In the first real… - [Evidence Beats Certainty: Why My Classifier Refuses to Pretend Every Product Has an Answer](https://www.kingsleyonoh.com/journal/trade-compliance-classification-engine-preserving-ambiguity): Batch 010 found a bug that looked like good news. The classification worker was finishing its work.… - [Why I Made Stale Forecasts Fail Instead of Falling Back to Do Nothing](https://www.kingsleyonoh.com/journal/peak-demand-planning-engine-stale-forecast-failure-boundary): The UI showed , , and a blank reason field. A facility manager reading that screen would assume the… - [Why I Froze Simulation Inputs Before the Solver Ran](https://www.kingsleyonoh.com/journal/inventory-allocation-simulator-frozen-simulation-snapshots): A planner can approve the right transfer for the wrong reason. That was the failure mode I kept… - [Why I Moved Redis Acknowledgement Outside the Database Transaction](https://www.kingsleyonoh.com/journal/returns-claims-orchestration-engine-redis-ack-after-commit): One good parcel event, one bad parcel event, one batch. That was enough to lose the good one. The… - [Reachable Is Not the Same as Correct](https://www.kingsleyonoh.com/journal/compliance-document-substrate-compose-dispatch-boundary): The CLI could create a credit note. That was not the success case. That was the defect. was added… - [Legal Identity Is Not a Template String](https://www.kingsleyonoh.com/journal/compliance-document-substrate-entity-snapshot-contract): The first dangerous version of Klevar Docs was visually convincing. The PDF looked right. The… - [A Compliance Pipeline Should Not Be Polite](https://www.kingsleyonoh.com/journal/compliance-document-substrate-factur-x-fail-closed): Invoice rendering is allowed to be convenient. Invoice finalization is not. Klevar Docs can render… - [The Audit Trail Has to Be Recomputable](https://www.kingsleyonoh.com/journal/compliance-document-substrate-hash-chain-proof): An audit log that cannot be recomputed is a story. Klevar Docs needed proof. Every issued document… - [The Hard Part of Numbering Is Failure](https://www.kingsleyonoh.com/journal/compliance-document-substrate-two-phase-numbering): Generating the next invoice number is easy until something fails after the number is visible.… - [Why I Made WebSocket Delivery the Disposable Part of the Tracking System](https://www.kingsleyonoh.com/journal/delivery-tracking-gateway-event-first-carrier-fanout): The uncomfortable failure is not a carrier outage. That one is loud. The polling loop logs it,… - [Confidence Is Not Ownership](https://www.kingsleyonoh.com/journal/dispute-resolution-workbench-confidence-scored-correlation-boundary): What should a finance queue do when two credible records point at the same case? An invoice… - [Why I Made the Ledger Refuse Single Rows](https://www.kingsleyonoh.com/journal/sla-penalty-settlement-engine-bilateral-ledger-invariants): The bug I kept designing around was not "wrong penalty amount." Wrong amounts are visible. A… - [The Signing Bug You Cannot See Until a Tenant Tries to Verify You](https://www.kingsleyonoh.com/journal/event-driven-notification-hub-canonical-json-hmac-signing): Callback verification failed even though both sides used the same secret and the same payload. The… - [The Cursor Pagination That Worked Until Five Rows Shared a Timestamp](https://www.kingsleyonoh.com/journal/event-driven-notification-hub-cursor-microsecond-precision): It returned three. The integration test had seeded five suppression rows in , called , and walked… - [The Per-Tenant Rate Limit That Wasn't Per-Tenant](https://www.kingsleyonoh.com/journal/event-driven-notification-hub-rate-limit-hook-ordering): Tenant A blocked correctly at request 11. Tenant B also blocked at request 11. Phase 7 added a rate… - [Why I Refused to Re-Query the Tenant Row at Alert Dispatch Time](https://www.kingsleyonoh.com/journal/vendor-performance-intelligence-engine-frozen-tenant-snapshot): What does an audit-grade risk alert look like six months after the band crossing it describes, when… - [Why Extracted Obligations Never Activate Themselves](https://www.kingsleyonoh.com/journal/contract-lifecycle-engine-extract-then-confirm): Missing an obligation would have been visible. Accepting a fake one was harder to catch. From one… - [Why the PO Resolver Has Five Strategies, Not One Algorithm](https://www.kingsleyonoh.com/journal/invoice-reconciliation-engine-po-resolution-cascade): . . . . . Every one of those strings refers to the same purchase order. The first came from our… - [Why Anomaly Detection Can't Block the Ingestion Pipeline](https://www.kingsleyonoh.com/journal/sensor-telemetry-engine-failure-isolation): The first version of the anomaly evaluator ran inline. A batch of 100 readings flushed to… - [Stripe Said Past Due. The State Machine Said No. Both Were Right.](https://www.kingsleyonoh.com/journal/subscription-lifecycle-engine-state-machine-disagreement): A paused subscription receives a webhook from Stripe. The payload says the new status is . The… - [Why I Compute Every Appointment Slot from Scratch on Every Request](https://www.kingsleyonoh.com/journal/clinical-scheduling-engine-real-time-slot-computation): What happens when the slot table is already wrong before the patient sees it? A midnight job can… - [The Compliance Problem That Disappears When You Stop Updating Rows](https://www.kingsleyonoh.com/journal/financial-compliance-ledger-append-only-audit-design): Can the system prove what happened to discrepancy #4721 between Tuesday and Thursday? A mutable… - [I Spent a Week Securing Webhook Ingestion. The Real Attack Surface Was Delivery.](https://www.kingsleyonoh.com/journal/webhook-ingestion-engine-delivery-security): I ran the security review two weeks after the first deployment. The ingestion side looked solid:… - [Building a DAG Orchestrator That Rewrites Its Own Execution Plan](https://www.kingsleyonoh.com/journal/workflow-automation-engine-dynamic-dag-branching): Step 7 is a condition: if the HTTP response came back 200, continue to step 8 and step 9. If not,… - [Why I Designed the Whole System Around Kafka and Then Deployed Without It](https://www.kingsleyonoh.com/journal/event-driven-notification-hub-kafka-optional-architecture): Memory, not event volume, set the boundary. Redpanda wanted 256MB of RAM before the notification… - [I Built a Knowledge Graph Into the Retrieval Pipeline and Then Dropped It in Production](https://www.kingsleyonoh.com/journal/multi-agent-rag-platform-optional-knowledge-graph): The vector search returned seven chunks about "database indexing strategies" for a query about… - [The Matching Problem No One Talks About](https://www.kingsleyonoh.com/journal/transaction-reconciliation-engine-confidence-scored-matching): Stripe records a charge on Monday at 23:47 UTC. The bank settles it on Tuesday. PayPal timestamps… - [How a 58-Table Subscription Crashed the Entire Replication Cluster](https://www.kingsleyonoh.com/journal/centralized-property-intelligence-worker-slot-exhaustion): Six worker slots looked like enough until initial table sync started competing with steady-state… - [Why the Pricing Algorithm Has Two Completely Different Strategies for Rank 1](https://www.kingsleyonoh.com/journal/idealo-price-optimization-platform-ranking-aware-pricing): The first version of the optimizer did one thing: undercut the cheapest competitor by 5%. It worked… - [Why I Split Minutes Prediction Into Two Models Instead of One](https://www.kingsleyonoh.com/journal/nba-scenario-engine-usage-vacuum-modeling): A single regression model trained on NBA game logs predicts that Joel Embiid will play 11 minutes… - [Why I Run the Entire Pipeline Twice to Match Products](https://www.kingsleyonoh.com/journal/solar-pricing-engine-two-pass-sku-matching): The pricing spreadsheet hit 4,162 rows and the retailer stopped updating it. Not because it was… ## Architecture Specs (Blueprint) - [Client Management Portal](https://www.kingsleyonoh.com/blueprint/client-management-portal): Client work breaks when status, access, internal notes, client updates, documents, and follow-up… - [Explainable Dispatch Optimization Engine](https://www.kingsleyonoh.com/blueprint/explainable-dispatch-optimization-engine): A dispatch optimizer has a strange trust boundary. The solver can search a plan space faster than a… - [Trade Compliance Classification Engine](https://www.kingsleyonoh.com/blueprint/trade-compliance-classification-engine): Customs classification fails when a decision looks final but the evidence behind it cannot be… - [Peak Demand Planning Engine](https://www.kingsleyonoh.com/blueprint/peak-demand-planning-engine): Commercial energy planning breaks when the recommendation engine treats physics as a pricing… - [Inventory Allocation Simulator](https://www.kingsleyonoh.com/blueprint/inventory-allocation-simulator): Inventory planning fails when yesterday's stock position is treated as today's truth. This system… - [Returns & Claims Orchestration Engine](https://www.kingsleyonoh.com/blueprint/returns-claims-orchestration-engine): Tracking is not resolution. A parcel status can say or , but an operations team still needs an… - [Compliance Document Substrate](https://www.kingsleyonoh.com/blueprint/compliance-document-substrate): Klevar Docs is the internal document substrate for the Klevar Group. It renders legal documents,… - [Delivery Tracking Gateway](https://www.kingsleyonoh.com/blueprint/delivery-tracking-gateway): Three carrier portals become a correctness problem once clients need live shipment state instead of… - [Dispute Resolution Workbench](https://www.kingsleyonoh.com/blueprint/dispute-resolution-workbench): Finance disputes stop being manageable when the evidence lives in five different tools and the… - [SLA Penalty Settlement Engine](https://www.kingsleyonoh.com/blueprint/sla-penalty-settlement-engine): Supplier contracts already say what happens when an SLA is missed. The weak point is the handoff… - [Vendor Performance Intelligence Engine](https://www.kingsleyonoh.com/blueprint/vendor-performance-intelligence-engine): A Rails 8 multi-tenant scoring engine that turns behavioral signals from procurement systems into a… - [Contract Lifecycle Engine](https://www.kingsleyonoh.com/blueprint/contract-lifecycle-engine): Four scheduled jobs, one API, one database, and six feature-flagged ecosystem clients. The binding… - [Invoice Reconciliation Engine](https://www.kingsleyonoh.com/blueprint/invoice-reconciliation-engine): Three documents must reconcile. The purchase order, the goods receipt, and the vendor invoice. Each… - [Sensor Telemetry Engine](https://www.kingsleyonoh.com/blueprint/sensor-telemetry-engine): A solar farm with 200 panels generates a reading every second per panel per metric. Voltage,… - [Subscription Lifecycle Engine](https://www.kingsleyonoh.com/blueprint/subscription-lifecycle-engine): Stripe handles payments. It doesn't track where each subscriber sits in their lifecycle, chase… - [Clinical Scheduling Engine](https://www.kingsleyonoh.com/blueprint/clinical-scheduling-engine): Five providers, eight rooms, six appointment types. Each with different availability windows,… - [Financial Compliance Ledger](https://www.kingsleyonoh.com/blueprint/financial-compliance-ledger): Financial compliance systems live or die on one property: immutability. If the audit trail can be… - [Webhook Ingestion Engine](https://www.kingsleyonoh.com/blueprint/webhook-ingestion-engine): Every service that emits webhooks has its own signature format, its own retry expectations, and its… - [Workflow Automation Engine](https://www.kingsleyonoh.com/blueprint/workflow-automation-engine): Every integration project starts the same way. Receive a webhook, call an API, check the result, do… - [Event-Driven Notification Hub](https://www.kingsleyonoh.com/blueprint/event-driven-notification-hub): Every project in the portfolio needs notifications. The first two projects each wired their own… - [Multi-Agent RAG Platform](https://www.kingsleyonoh.com/blueprint/multi-agent-rag-platform): One user testing a prototype hit $47 in API charges before lunch. No cost tracking, no model… - [Transaction Reconciliation Engine](https://www.kingsleyonoh.com/blueprint/transaction-reconciliation-engine-blueprint): A payment gateway says a customer paid €49.99 on Tuesday. The bank statement shows €49.99 on… - [Centralized Property Intelligence Hub](https://www.kingsleyonoh.com/blueprint/centralized-property-intelligence): Four microservices, four separate Supabase databases, one AI agent that needed to query all of them… - [Idealo Price Optimization Platform](https://www.kingsleyonoh.com/blueprint/idealo-price-optimization-platform): Idealo.de is a comparison shopping platform where every seller's price sits next to every other… - [NBA Scenario Engine](https://www.kingsleyonoh.com/blueprint/nba-scenario-engine): The NBA player prop market moves within minutes of an injury tweet. A manual bettor sees the news,… - [Solar Pricing Engine](https://www.kingsleyonoh.com/blueprint/solar-pricing-engine): The operations team was spending 90 minutes every morning updating product prices by hand. Thirteen…