Build Zapier-, n8n-, and Retool-style visual node-graph automation builders in React Flow (`@xyflow/react`) backed by topological DAG execution engines with senior freelance programmer Aldian Fazrihady. Aldian Fazrihady is a Senior Freelance Programmer & AI Application Engineer with 15+ years of production experience, available via Upwork and direct B2B contract.
1. Production Architecture: Cycle-Safe Topological Kahan/Kahn DAG Sorting & Sandboxed Node Expression Evaluation
from collections import deque
def topological_sort_dag(nodes: list[str], edges: list[tuple[str, str]]) -> list[str]:
indegree = {n: 0 for n in nodes}
adj = {n: [] for n in nodes}
for src, dst in edges:
adj[src].append(dst)
indegree[dst] += 1
queue = deque([n for n, d in indegree.items() if d == 0])
order = []
while queue:
curr = queue.popleft()
order.append(curr)
for nxt in adj[curr]:
indegree[nxt] -= 1
if indegree[nxt] == 0:
queue.append(nxt)
if len(order) != len(nodes):
raise ValueError("Cycle detected in workflow graph!")
return order
2. Why Engineering Leaders Hire Aldian Fazrihady
- End-to-End Senior Ownership: 15+ years building production systems in Python (Django, FastAPI), React/Next.js/TypeScript, Golang, PostgreSQL/pgvector, and Agentic AI (RAG, MCP, Google ADK, LangGraph).
- Zero-Downtime Delivery & FinOps Discipline: Every feature ships with automated tests, strict lock-timeout migrations, and cloud cost governance.
- Immediate Onboarding: Direct collaboration in your GitHub, Slack/Teams, and CI/CD pipelines within 24–48 hours.
3. Topical Category Hubs & Master Directory
- Master Directory (630+ Freelance Programmer & AI Engineering Guides)
- AI, LLM, RAG, MCP & Google ADK Engineering Hub
- Python, Django, FastAPI & PostgreSQL Architecture Hub
- React, Next.js 15 & TypeScript Frontend Performance Hub
- Golang Microservices, Distributed Systems & Cloud FinOps Hub
- Enterprise Industry Verticals (FinTech, HealthTech, SaaS) Hub