Architecture

How DNS Migrator's components fit together.

High-Level Overview

┌──────────────────────────────────────────────┐
│           Frontend (Web UI)                  │
│  Tailwind CSS · 4-step wizard · NDJSON logs  │
└──────────────────┬───────────────────────────┘
                   │ REST API (POST)
┌──────────────────▼───────────────────────────┐
│           Backend API Layer                  │
│  Express (local) or Cloudflare Workers       │
└───┬──────────┬──────────┬──────────┬─────────┘
    │          │          │          │
┌───▼───┐ ┌───▼────┐ ┌───▼───┐ ┌───▼──────┐
│ Azure │ │Cloudfl.│ │  DNS  │ │Transform │
│  API  │ │  API   │ │ Scan  │ │  Logic   │
│Module │ │ Module │ │ (DoH) │ │          │
└───────┘ └────────┘ └───────┘ └──────────┘

Components

Frontend (public/)

File	Purpose
index.html	Dark-themed wizard UI built with Tailwind CSS
app.js	State management, step navigation, NDJSON stream parsing

The frontend is a single-page application with a 4-step wizard:

1. Cloudflare — Token validation, account selection
2. DNS Source — Choose Scan, Azure, or Manual
3. Domains — Select zones with record counts
4. Migrate — Live streaming log with colour-coded results

Backend Modules (src/)

Module	Purpose
api.js	Express route definitions and request handling
azure.js	Azure DNS Management API integration (zone listing, record export)
cloudflare.js	Cloudflare API integration (zone creation, record insertion, duplicate detection)
dns-scan.js	DNS-over-HTTPS scanning via Cloudflare DoH (probes ~80 common subdomains)
transform.js	Record normalisation — strips FQDNs, removes trailing dots, maps Azure → Cloudflare format

Serverless Functions (functions/api/)

Mirror of the src/ modules adapted for Cloudflare Workers runtime:

Function	Endpoint
cloudflare/validate.js	/api/cloudflare/validate
azure/validate.js	/api/azure/validate
azure/zones.js	/api/azure/zones
dns/scan.js	/api/dns/scan
migrate.js	/api/migrate
_helpers.js	Shared NDJSON streaming utilities

PowerShell Scripts

Script	Purpose
Migrate-DNS.ps1	Single-zone migration from Azure DNS to Cloudflare
Migrate-Batch.ps1	Multi-zone batch migration using JSON config

Data Flow

Web UI Migration Flow

User enters Cloudflare token
        ↓
POST /api/cloudflare/validate
        ↓ returns accounts
User selects account, chooses DNS source
        ↓
┌───────────────────────────────┐
│  Scan: POST /api/dns/scan     │
│  Azure: POST /api/azure/zones │
│  Manual: client-side only     │
└───────────────┬───────────────┘
                ↓
User selects zones (checkboxes)
                ↓
POST /api/migrate (NDJSON stream)
                ↓
For each zone:
  1. Create zone in Cloudflare (or use existing)
  2. Fetch records from source
  3. Transform records (strip FQDN suffixes, normalise)
  4. Check for duplicates in Cloudflare
  5. Push new records via Cloudflare API
  6. Stream per-record status back to UI
                ↓
Display nameservers for registrar update

PowerShell Migration Flow

Migrate-DNS.ps1 / Migrate-Batch.ps1
        ↓
az network dns record-set list (Azure CLI)
        ↓
Convert-AzureToCloudflareRecords (transform)
        ↓
Cloudflare API: POST /zones/{id}/dns_records
        ↓
Console output: created / skipped / failed per record

Real-Time Streaming

The /api/migrate and /api/dns/scan endpoints use NDJSON (newline-delimited JSON) for real-time progress:

{"type":"status","zone":"example.com","message":"Creating zone..."}
{"type":"success","zone":"example.com","message":"Zone created"}
{"type":"record","zone":"example.com","message":"[1/10] A www → 1.2.3.4"}
{"type":"skip","zone":"example.com","message":"[2/10] CNAME mail — already exists"}
{"type":"zone-complete","zone":"example.com","result":{"created":9,"skipped":1,"failed":0}}
{"type":"done","results":[...]}

Supported Record Types

Type	Supported	Notes
A		IPv4 address
AAAA		IPv6 address
CNAME		Canonical name
MX		Mail exchange (includes priority)
TXT		Text records
SRV		Service records (priority, weight, port)
CAA		Certificate Authority Authorization
NS		Non-apex only (apex NS skipped)
PTR		Pointer records
SOA		Skipped (Cloudflare manages SOA)