MarginDelta

How MarginDelta detects silent cost regressions — system design and product flow.

01 — System Architecture

AWS EC2 · ap-south-1 · Mumbai · Production

Target Service

customer-dashboard-demo

FastAPI · Docker

:8080

POST /api/v2/reports

26 DB calls · N+1

POST /api/v1/reports

2 DB calls · baseline

/metrics

→

15s

Metrics Store

Prometheus

prom/prometheus:latest

:9090

Scrapes every 15s
Stores time-series
HTTP Query API

HTTP

→

query

RCA Engine

prometheus_reader.py

reads live signals

cost_regression_engine.py

anomaly · leakage · RCA

monitor.py

5min loop · alerts

JSON

→

reports/

Dashboard

Streamlit

python:3.11-slim

:8501

Cost Regression RCA
Alert History
Nginx → HTTPS

app.margindelta.com ✅

🐳 Docker Compose · 4 containers

🔒 SSL · Let's Encrypt · Sept 2026

🌐 DNS · Route 53 · margindelta.com

📧 Email · AWS SES · Zoho Mail

💾 Storage · 20GB gp3

🖥 OS · Ubuntu 24.04 LTS

02 — Product Flow

Customer Deploys

Engineer pushes v2.0.0. N+1 query introduced silently. No alerts fired.

POST /api/v2/reports

→

traffic
flows

Prometheus Scrapes

/metrics scraped every 15s. DB calls, latency, cost signals captured.

prometheus_reader.py

→

every
5 min

Engine Detects

Anomaly score: 94/100. Multiplier: 25x. Projected leakage: $24,000/mo.

cost_regression_engine.py

→

RCA
built

AI RCA Generated

Root cause identified. Slack + Jira drafts auto-generated. Owner tagged.

build_ai_rca_summary()

→

JSON
report

CTO Sees It

app.margindelta.com shows $24,000 leak. One click — full RCA, fix, owner.

app.margindelta.com ✅

💡 MarginDelta Value

Deploy at 9am → detected 9:05am → CTO notified → fix merged same day

$24,000/mo saved

AWS Cost Explorer

Shows bills. No deployment correlation.

❌ No RCA

Datadog

Shows metrics. You build the alerts.

❌ No cost RCA

Compute Optimizer

Rightsizing only. No code regression.

❌ No deploy link

MarginDelta ✓

Deploy → detect → RCA → owner → fix. Automatic.

✅ Full pipeline

Architecture Overview