Oscar Ndugbu
Staff Backend and Platform Engineer
I build resilient architectures designed for high availability and easy maintenance. My work makes failure visible, recovery deliberate, and day-to-day operations simple to understand.
Operating model
UTC+1
Staff Backend and Platform Engineer
I build resilient architectures designed for high availability and easy maintenance. My work makes failure visible, recovery deliberate, and operations easier to understand.
Focus
Backend · platform reliability
Proof
TaxBridge · SabiScore · SwarmXQ
Method
Constraint → decision → outcome → evidence
Each case study starts with the constraint, explains the architecture decision, and shows the resulting behaviour and available evidence.
Tax workflow automation designed to keep tenant boundaries, retries, and audit history explicit — so deadline-driven filing can recover cleanly.
TaxBridge Reliability Ledger
Constraint
Rate-limited tax submission during deadline bursts, with duplicate filing risk on retry.
Decision
Database RLS plus idempotent BullMQ jobs keyed to submission content.
Outcome
Retries can resume without re-submitting a completed filing operation.
Evidence
Private architecture record · source available to verified employers.
Tax workflow automation for Nigerian small businesses. PostgreSQL RLS enforces tenant isolation at the database level, while BullMQ jobs use submission-derived idempotency keys so retries do not create duplicate filings. Hash-chained audit records preserve a traceable history. NRS DigiTax integration remains in progress.
An ensemble ML platform that keeps prediction delivery useful through cache failures, retraining, and dependency loss.
SabiScore Reliability Ledger
Constraint
Inference and model-health signals must remain usable through cache or feature-store failure.
Decision
FastAPI serving, versioned Redis caching, Pub/Sub fan-out, and a lower-confidence fallback model.
Outcome
Dependency failure returns a labelled lower-confidence result instead of stale output or an opaque error.
Evidence
Public source · architecture case study; performance artifacts are not published.
Multi-agent orchestration that routes work to the right model, exposes system state to operators, and recovers from interrupted runs.
SwarmXQ Reliability Ledger
Constraint
Local inference must stay correct under constrained memory and intermittent third-party connectivity.
Decision
Task-specific model routing with checkpointed state and bounded fallbacks.
Outcome
Failed work resumes from the last consistent checkpoint instead of restarting the run.
Evidence
Public source · architecture case study.
A structured short-form video pipeline that turns a topic or brief into a publish-ready creative package while keeping resource pressure and recovery visible.
The Yap Engine Reliability Ledger
Constraint
Short-form video generation must survive constrained CPU/RAM resources and partial failures without turning a long-running job into an opaque restart.
Decision
Stage the pipeline from intent through finalization, route work to task-specific local models, and enforce explicit queue, timeout, and resource-pressure boundaries.
Outcome
Creative work has visible stage boundaries, recoverable job state, and deliberate degradation paths across inference and media generation.
Evidence
Public source · architecture case study.
Zero-knowledge verification for document integrity without exposing the underlying document.
Hashablanca Reliability Ledger
Constraint
Verify document integrity without exposing the document or exceeding verifier gas budgets.
Decision
Groth16 proofs generated off-chain with per-network verification adapters.
Outcome
Integrity can be checked without revealing document contents.
Evidence
Public source · architecture case study.
Federal education reporting across 36 state sources, designed to keep partial submissions moving without hiding data quality issues.
UBEC Data Pipeline Reliability Ledger
Constraint
Late and partial state submissions must not block every completed report.
Decision
Isolated Airflow task groups per state, followed by cross-state validation gates.
Outcome
Thirty-five state reports can proceed while one delayed source remains visibly pending.
Evidence
Private federal engagement · architecture case study.
The evidence is strongest when the failure boundary is named: what can break, how the system responds, and which record supports the claim.
COMPLIANCE PLATFORM · FINTECH
Duplicate filing and tenant leakage are designed out of the critical path.
BullMQ absorbs NRS API rate limits with idempotent submission keys. PostgreSQL RLS keeps tenant isolation at the database engine, while the case study records the integration status and private evidence path.
Chosen: RLS at engine level, not application-layer filtering — NRS audit scrutiny demands proof that tenant data cannot cross-contaminate.
ML PLATFORM · OBSERVABILITY
Inference stays useful when cache or feature-store dependencies fail.
Versioned Redis caching and a lower-confidence baseline model provide a deliberate degraded path. The measured record is bounded to a 90-day Prometheus window and a named reactive-alerting baseline.
Chosen: FastAPI + Redis Pub/Sub — sub-50ms event fan-out at sustained load, impossible with synchronous polling under concurrent sessions.
AI AGENT PLATFORM · ORCHESTRATION
Agent work resumes from a known state instead of replaying the entire run.
Task-specific model routing operates within an 8GB local-inference budget. Checkpointed state, timeout budgets, and bounded fallbacks make partial failure visible and recoverable.
Chosen: Autonomous evolution layer over static agent configs — manual tuning cannot adapt to novel inputs at scale.
FEDERAL INFRASTRUCTURE · DATA
One late state submission does not block every completed report.
Isolated Airflow task groups, canonical ingest schemas, probabilistic record linkage, and cross-state validation gates keep partial output explicit across 36 state sources.
Chosen: Probabilistic deduplication over exact-match — state submissions use inconsistent school name spellings across ministries.
Four source-linked packages and experiments focused on tenant isolation, auditability, incident triage, and local-model routing. Each card names the evidence path it can actually support.
The evidence contract is simple: public-source claims link to public source; private project context is not presented as third-party verification.
Node.js · PostgreSQL
Public sourceA PostgreSQL Row-Level Security helper for moving tenant-isolation policy closer to the database boundary instead of relying only on application checks. The repository documents the implementation and its intended use in multi-tenant systems.
Fintech · Auditability
Public sourceA hash-linked audit-log pattern designed to make retrospective record changes detectable during integrity checks. The public repository exposes the implementation so the chain construction and verification approach can be inspected directly.
AI · DevOps
Public sourceAn incident-triage experiment that turns logs and traces into ranked root-cause suggestions for operator review. Its public source makes the input path and ranking workflow inspectable without presenting an unmeasured time-savings claim.
AI · Agent Orchestration
Source-linkedA local-model routing pattern derived from SwarmXQ. It assigns task classes to different GGUF models and defines fallback chains, with the linked public SwarmXQ source providing the inspectable evidence path for the routing approach.
Public evidence paths are available on GitHub.
The stack is organized by operational responsibility: isolation, observability, recovery, data movement, and delivery. Each tool maps to a recorded system decision rather than a generic proficiency list.
Isolation
data boundary
TaxBridge · Fastify 5 · PostgreSQL 15 RLS
Telemetry
operating signal
SabiScore · XGBoost · LightGBM · Prometheus
Recovery
failure path
SwarmXQ · Ollama GGUF · Checkpoint Recovery
Core production stack
Default view is intentionally curated for fast trust. Open the full explorer only when you want deep implementation coverage across all 62 tools.
+6 more in the full explorer below.
Production system × skill lineage
Full explorer · 62 tools · 8 pillars
Expanded layer for CTO and engineer-level scrutiny. Optional by design to preserve reading momentum for recruiters and founders.
More than a decade in federal data systems shaped this approach to software: start with the constraint, make failure visible, and design recovery before it is needed.
Work at UBEC reinforced a discipline for incomplete inputs and partial results without hiding what is missing. That discipline now carries into every system: make failure visible, make recovery deliberate, and leave enough context for the next engineer to operate the system with confidence.
TaxBridge combines a mobile workflow with Fastify 5, PostgreSQL 15 RLS, and durable job processing so tenant data stays separated and retries do not create duplicate work. SabiScore pairs ensemble ML inference with a Next.js dashboard, caching, telemetry, and a labelled fallback path. SwarmXQ uses checkpointed agent orchestration so interrupted work can resume instead of starting from zero.
The resume gives the professional history; public repositories show the engineering record. Where evidence is private, that boundary stays explicit rather than turning an internal observation into a public metric.
Engineering Standards · Non-Negotiable
Correctness belongs to the whole product.
The data model, API, and interface must agree on what is true. Reliability cannot be delegated to the last layer in the request path.
Failures should be visible and recoverable.
Retries, dead-letter handling, structured logs, and metrics make a failure diagnosable before it becomes a prolonged incident.
Important decisions should leave a trail.
A good decision record explains the choice, the trade-off, and what was deliberately rejected — so the system remains maintainable after handoff.
Observability is part of the product.
Health checks, traces, and dashboards turn hidden failure into actionable information for the people operating the system.
Applied across TaxBridge · SabiScore · SwarmXQ
Based in Lagos. Operating on UTC+1.
Architecture, ML systems, failure modes, and the decisions behind them — written for engineers who need the reasoning, not just the result.
Start here if you want to understand how these systems were designed.
How variable power, network, and regulatory conditions shape more resilient infrastructure decisions. Constraint is treated as a design input, not a branding claim.
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Systems that work at 2am.
That's the standard.