Charles Mark - AI Systems Engineer
Charles MarkAI Systems Engineer / Backend / Automation

I BUILD AI-POWERED SYSTEMS THAT SOLVE REAL PROBLEMS.

Engineering disciplines: AI Systems Engineer, Backend Engineer, and Workflow Automation Engineer.

From backend services to intelligent agents and automated workflows, I turn practical problems into engineered solutions.

CV updated & available upon inquiry•Production-minded delivery
INTERACTIVE SYSTEM ARCHITECTURE
Click any component to inspect flow
Backend API Gateway
ROUTING & SECURITY

Validates input schemas, enforces rate limits, manages JWT sessions, and delegates tasks to agents or pipelines.

Zod / Pydantic schemasRedis token bucketRole-based access (RBAC)
ENGINEERING DISCIPLINES

Production focus & applied technical capabilities

AI SYSTEMS
Agentic loops & LLM pipelines
BACKEND DEV
Scalable REST APIs & PostgreSQL
WORKFLOW AUTO
n8n & event-driven webhooks
API CONTRACTS
Resilient schemas & data mapping
CLOUD INFRA
Containerized & reproducible apps
FEATURED ENGINEERING WORK

APPLIED AI, WORKFLOWS & BACKEND SERVICES

View All Engineering Projects (5)
INTERACTIVE SYSTEM ARCHITECTURE STUDIO

Klinik Voice Intake & Triage Pipeline

Real-time stateful voice agent architecture with deterministic clinical triage routing

PATTERN: Async WebSockets + LangGraph State Machine
Sub-850ms audio-to-triage turnaround with zero hallucinated diagnoses
SYSTEM EXECUTION PIPELINE (TAP ANY NODE TO INSPECT)
STEP 0118ms

Audio Ingest Stream

Client Microphone Feed
WebSocket / 16kHz PCM
STEP 02240ms

Speech-to-Text Pipeline

Whisper Transcription Core
gRPC Streaming
STEP 03320ms

LangGraph State Machine

Clinical Decision Graph
Python / Async Graph Loop
STEP 048ms

Pydantic Schema Guard

Deterministic Validation
Zod / Pydantic V2
STEP 0565ms

EMR & Dispatch Gateway

Clinical Record Persistence
HTTPS / REST FHIR
STEP 01 OF 05WebSocket / 16kHz PCM

Audio Ingest Stream

Role: Client Microphone Feed
ARCHITECTURAL ROLE & BEHAVIOR

Captures spoken patient audio chunks in real-time over bi-directional duplex WebSockets with voice activity detection (VAD).

ESTIMATED LATENCY: 18msTRANSPORT: WebSocket / 16kHz PCM
AI SystemsHackathon Prototype (Proof of Concept)

Klinik — AI Healthcare Voice Assistant

Voice-driven patient intake & triage agent prototype built for medical hackathons

PROBLEM SOLVED:

Patient intake during high-pressure emergency or clinic admissions is often bottlenecked by manual paperwork and fragmented transcription, delaying critical triage information.

WHAT I BUILT & DELIVERED:

Engineered an interactive conversational voice assistant agent that captures spoken symptom descriptions, extracts structured clinical observations, and routes them through a stateful LangGraph workflow.

FastAPILangGraphPythonOpenAI Whisper / LLM APIsWebSocketsPydantic
AutomationProduction Pipeline

Multi-Channel AI Workflow Automation System

Event-driven business pipeline uniting webhooks, AI document parsing, and instant notifications

PROBLEM SOLVED:

Operations teams spend dozens of hours weekly manually copying lead inquiries, sorting attachments, extracting invoice parameters, and manually notifying account executives.

WHAT I BUILT & DELIVERED:

Architected an end-to-end event-driven n8n automation pipeline that captures multi-source webhooks, parses unstructured incoming emails and PDF attachments via LLM function calling, writes structured records to PostgreSQL, and dispatches role-tailored alerts.

n8nWebhooksREST APIsNode.jsOpenAI APIPostgreSQLSlack / Email
AI SystemsWorking System

Enterprise Document RAG Knowledge Assistant

Semantic search and grounded question-answering system over private technical documentation

PROBLEM SOLVED:

Engineers and support teams struggle to locate precise answers within hundreds of pages of API specifications, architecture decision records, and operational runbooks.

WHAT I BUILT & DELIVERED:

Built a retrieval-augmented generation (RAG) assistant that indexes internal Markdown and PDF documentation into pgvector, applies hybrid keyword-vector retrieval, and provides cited, verifiable answers.

PythonFastAPIPostgreSQL (pgvector)LangChainOpenAI EmbeddingsDocker
BackendImplemented Service

Scalable REST API & Data Service

High-performance backend API with relational data modeling, RBAC, and transactional integrity

PROBLEM SOLVED:

Modern applications require secure, auditable, and performant backend services that handle concurrent requests without data race conditions or silent failures.

WHAT I BUILT & DELIVERED:

Designed and developed a production-ready RESTful backend service with TypeScript, role-based access control (RBAC), robust input validation, database connection pooling, and structured error logging.

Node.jsExpress.jsTypeScriptPostgreSQLPrisma/KnexJestDocker
CORE SERVICES & OFFERINGS

ENGINEERED SOLUTIONS FOR APPLIED AI & BACKENDS

I build practical, durable systems tailored to your workflows and infrastructure — avoiding fragile demos and unnecessary complexity.

SERVICE 01
AI Workflow Automation

STOP REPEATING TASKS AI CAN HELP AUTOMATE.

I build intelligent workflows that help businesses reduce repetitive work, organize information, and streamline everyday processes.

CAPABILITIES INCLUDED
  • Email and customer inquiry automation
  • Lead capture and follow-up workflows
  • AI-powered document processing & PDF data extraction
  • Business process automation with self-hosted or cloud n8n
  • API-connected workflows and multi-channel notifications (Slack, Email, CRM)
SERVICE 02
Custom AI Agents & Assistants

TURN AI INTO A MORE USEFUL ASSISTANT.

I build AI-powered assistants and agent workflows tailored to specific tasks, information sources, and business needs.

CAPABILITIES INCLUDED
  • Custom task-oriented AI assistants
  • Automated research, summarization, and reporting workflows
  • Knowledge assistants grounded in private business documents (RAG)
  • AI agents safely connected to permitted tools and external APIs
  • Structured AI workflows with error handling, guardrails, and validation
SERVICE 03
Backend Development & AI Integration

HAVE AN IDEA? LET'S BUILD THE SYSTEM BEHIND IT.

I develop backend services and integrate AI capabilities into applications, helping turn product ideas into working software.

CAPABILITIES INCLUDED
  • REST API development and secure third-party integration
  • Backend services, data modeling, and PostgreSQL database design
  • AI model and LLM API integration with streaming responses
  • Connecting applications, internal tools, and business systems
  • Application logic, data processing, authentication, and role management
ENGINEERING METHODOLOGY

HOW I WORK: FROM PROBLEM TO PRODUCTION

A disciplined, step-by-step engineering process designed to eliminate ambiguity, guarantee reliability, and ensure long-term maintainability.

STAGE 01 / 05

Understand

“Deconstruct the business problem & define measurable outcomes”

Before writing any code or configuring pipelines, we identify exactly where the human friction occurs, quantify data formats, and determine failure tolerance.

ENGINEERING CONSIDERATION:

Preventing scope creep and eliminating low-value automation attempts early.

KEY DELIVERABLES
  • Process flow diagram & input/output contract
  • Identification of API access boundaries & security requirements
  • Cost-benefit estimation & automated vs. human-review thresholds
TECHNICAL PROFICIENCY MATRIX

PROVEN STACK & HONEST CAPABILITIES

Technologies grouped by architectural role. Transparently distinguished between production-implemented systems and active research labs.

Backend Engineering

5 Technologies

Developing robust, scalable server-side systems, API contracts, and business logic.

JavaScript / TypeScriptProduction

Primary languages for building type-safe backend architectures and APIs.

Node.js & Express.jsProduction

Extensive experience building RESTful services, middleware, and async handlers.

REST APIs & ArchitectureProduction

Design, versioning, status codes, payload validation, and documentation standards.

Django & Django REST FrameworkHands-on

Python-based web services, ORM modeling, serializer validation, and viewsets.

NestJSHands-on

Modular, decorator-driven architecture with TypeScript dependency injection.

FREE CONTENT & EDUCATIONAL RESOURCES

PRACTICAL ARCHITECTURE & AUTOMATION GUIDES

Explore All Free Guides (5)100% Free • Open Technical Blueprints • No Paywall
FREE GUIDEAutomation
5 min read

How to Identify a Business Process Worth Automating

Not every repetitive task deserves an automated pipeline. Here is an engineer's framework for assessing ROI, failure tolerance, and data readiness before writing a single line of automation.

KEY LESSON INSIDE:
High volume + low ambiguity is the ideal automation candidate.
October 2024Read Free Guide
FREE GUIDEAI Systems
6 min read

What Makes an AI Agent Different from a Simple Chatbot?

Beyond the marketing buzzwords: a technical look at how state persistence, tool execution, and cyclical evaluation loops separate true agentic systems from standard conversational LLMs.

KEY LESSON INSIDE:
Chatbots are single-turn prediction engines; agents execute multi-step plans with tools.
October 2024Read Free Guide
TESTIMONIALS OF SUCCESS STORIES

PROVEN OUTCOMES.VERIFIED SUCCESS STORIES.

Direct feedback from technical leaders, founders, and engineering peers who partnered with Charles Mark on production AI systems, workflow automation, and backend architectures.

Workflow Automation

“Charles re-architected our intake workflow in n8n and Python. What used to take our ops team 14 hours a week across HubSpot and Postgres now runs autonomously with full error logging and zero data loss.”

Saved 14+ hrs/wk & eliminated data reconciliation errors
EL
Engineering LeadHead of Operations & Platform • SaaS Workflow Partner
Autonomous Agent System

“Unlike developers who just wire together basic OpenAI calls that break on edge cases, Charles brought real backend discipline with LangGraph and strict Zod validation. The agent handles ambiguous inputs gracefully.”

99.4% reliable execution on structured extraction
TF
Technical FounderFounder & CTO • AI Intelligence Studio
Backend & Systems

“Working with Charles on API infrastructure was seamless. He pays attention to idempotency, database indexing, and edge-case error propagation before touching any frontend code. A rare engineer who understands both modern AI and rock-solid backends.”

Sub-120ms p95 latency on high-throughput webhook receiver
SSE
Senior Software EngineerLead Backend Architect • Distributed Systems Team
ABOUT CHARLES MARK

BRIDGING SOLID BACKEND PRINCIPLES WITH APPLIED AI SYSTEMS.

I am an engineer interested in building practical AI-powered systems, reliable backend services, and automation that solves real problems.

Rather than treating AI as an isolated novelty, I ground LLMs and agent workflows in proven software foundations: relational database models in PostgreSQL, type-safe API contracts in Express/FastAPI, asynchronous queueing, and webhook security.

Engineering Over Hype

Focusing on verifiable uptime, schema validation, and low latency.

Transparent Capabilities

Evidence-backed skills and clearly demarcated research areas.

Read Full Background & StoryCV available upon direct request
Charles Mark - AI Systems Engineer
CHARLES MARKAI SYSTEMS ENGINEER
LOCATION:Global / Remote
SPECIALTY:AI + Backend
PRIMARY STACK:Express.js / Django / PostgreSQL
Direct Engineering Inquiries Open

LET'S BUILD SOMETHING USEFUL.

Have a business process to automate, an AI system to build, or an application that needs backend engineering? Tell me what you are working on.

Direct WhatsApp: +234 708 236 7382•No forms required • Direct engineer access