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Rahul Bhatt
Rahul Bhatt

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⚡️ Building a Multi-Tenant Spring Boot Starter from Scratch — with Subdomain Routing, Dynamic Datasources & Ego Logs

#springboot #java #opensource #multitenant

🚀 Building a Multi-Tenant Spring Boot Starter from Scratch

Developer Preview v0.1.0-SNAPSHOT is live!

🧠 Why This Starter Exists

Spring Boot lacks a true plug-and-play solution for multi-tenant SaaS platforms. Most solutions are deeply coupled, opinionated, or too abstract.

But also — this project came from a personal place.

Right after I received a disappointing 0.5 LPA raise (yes, backwards momentum), I decided to convert that frustration into engineering fire. Inspired by Blue Lock, I wanted to log every technical decision like a striker chasing goals — enter the ego-logs/ folder.

🧱 Project Structure 

├── starter/ → Core Spring Boot auto-config starter ├── demo/ → Sample app showing real usage ├── ego-logs/ → My engineering journal (yes, Blue Lock–style) ├── scripts/ → Placeholder for CI or future tools ├── daily/ → Temp debug + local artifacts
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🧩 Features in Developer Preview

✅ Subdomain-based tenant resolution
✅ Header-based tenant resolution
✅ Tenant registry (in-memory)
✅ Per-DB isolation strategy
✅ @EnableTenantIsolation annotation
✅ Clean Spring Boot auto-configuration
⚙️ Extensible resolvers + datasource logic

📦 Add It via JitPack

Maven 

<dependency> <groupId>com.github.rahul-s-bhatt</groupId> <artifactId>multi-tenant-springboot-starter</artifactId> <version>v0.1.0-SNAPSHOT</version> </dependency>
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Gradle 

dependencies { implementation("com.github.rahul-s-bhatt:multi-tenant-springboot-starter:v0.1.0-SNAPSHOT") }
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💻 Usage Snapshot

Enable the starter via application.yml 

multi-tenancy: default-tenant-id: acme registry: type: IN_MEMORY in-memory-tenants: - tenantId: acme datasourceUrl: jdbc:h2:mem:acme username: sa - tenantId: globex datasourceUrl: jdbc:h2:mem:globex username: sa isolation: type: TENANT_PER_DATABASE resolution: type: HTTP_HEADER
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🧠 How It Works 

flowchart TD A[Request] --> B[Filter: TenantResolver] B --> C[TenantContextHolder] C --> D[TenantRegistry] D --> E[RoutingDataSource] E --> F[DB A or DB B]
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🔥 About ego-logs/

This is my commitment to daily logging of what I learned, attempted, failed at, or broke. No GitHub green dots — real dev logs.

Just like Blue Lock's Ego Jinpachi believes in personal records to dominate the game, these ego logs are my engineering training arcs.

🛣️ What's Coming

  • JWT-based tenant resolution
  • Schema-based isolation
  • Runtime tenant onboarding APIs
  • Liquibase / Flyway integration
  • Multi-tenant Spring Security support

🧑‍💻 Contribute or Fork

If you're working on a SaaS platform, this is for you.
Star 🌟 the repo, fork it, build your own isolation strategy.

GitHub → rahul-s-bhatt/multi-tenant-springboot-starter
JitPack → jitpack.io/#rahul-s-bhatt

🫡 Final Words

Dev discipline isn't just commits — it's clarity, context, and ego-fueled progress.

This is just the beginning.

If you enjoyed this drop, follow @rahul_s_bhatt for future dev logs, open-source updates, and architecture deep dives.

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