Bablu Kumar Singh
Available for Full-Time Roles & Contracting

Backend & AI/Agentic engineer building SaaS platforms and the agents behind them

Node.js and PostgreSQL/MongoDB on the backend side, LLM orchestration and RAG pipelines on the AI side — schema design, agent architecture, and the problems that only show up once real usage hits.

Where most of the work actually goes

A few things come up on nearly every project: keeping the API layer sane, getting the database schema right early, not finding out about a bottleneck in production, and — increasingly — giving an LLM agent enough guardrails to be trusted with real actions.

APIs that don’t block

Express services that hand off slow work to a queue instead of making the request wait for it.

Schemas that hold up

Indexing and query patterns thought through up front, in both PostgreSQL and MongoDB — tenancy boundaries included.

Endpoints worth trusting

Validated inputs, versioned routes, and auth that’s actually been tested against the roles it’s supposed to restrict.

Agents that don’t run wild

Tool-calling loops with schema-validated inputs, guardrails on what they can touch, and a memory layer that won’t quietly blow the context window.

The stack, in practice

What's actually in use across current projects — not an exhaustive list, just what gets reached for.

Node.js

Expert

Event-driven, asynchronous runtime for scalable network systems.

Express.js

Expert

Fast, unopinionated, minimalist web framework for RESTful APIs.

TypeScript

Expert

Statically typed superset of JavaScript ensuring compile-time safety.

REST API Design

Expert

Building semantic, versioned, rate-limited, and scalable API structures.

A few things I've built

Case studies with the actual problem, the architecture, and what shipped — not just screenshots.

View all projects
ROI Spectrum
SaaS Platforms

ROI Spectrum

Node.jsExpress.jsPostgreSQLMongoDBReact.jsStripeRedis

The Problem: SEO agencies and website owners lacked an integrated, multi-tenant solution to track ROI, audit logs, service tracking, and automated subscription billing transparently.

Forklift CRM
CRM Applications

Forklift CRM

Node.jsExpress.jsMongoDBReact.jsSocket.ioZod

The Problem: Operations managers struggled to handle lead assignments, track workflow automations, and manage sales representatives with clean role-based permissions.

AgentCore
Generative AI

AgentCore

TypeScriptNode.jsZodOpenAI APIAnthropic APIGemini APINext.js

The Problem: Every LLM provider ships its own SDK, message format, and streaming API, so switching models, or falling back to a second provider when one is rate-limited, usually means rewriting the integration layer.

Memorybook
Generative AI

Memorybook

Node.jsTypeScriptExpress.jsDrizzle ORMPostgreSQL (pgvector + BM25)Neo4jInngestNext.js

The Problem: Tools like NotebookLM are useful for asking questions over your own documents, but they are closed products, no self-hosted option, no visibility into how retrieval or memory decisions actually get made.

GitHub activity

What the commit history actually looks like, day to day.

Open Source Activity

Simulating daily commit pushes, branches, and code reviews

3193 Contributions in the last year
MonWedFri
Learn more about my workflows on GitHub
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What working together looks like

Sample feedback, illustrative of the kind of work above — not direct quotes from a specific reviewer.

"Handed off the ROI Spectrum schema and Stripe webhook work and didn't have to think about it again — billing edge cases included."

E
Engineering lead
Previous role

"The CRM's lead-assignment logic needed real-time updates and a permissions model that wasn't a mess. Both landed clean on the first pass."

P
Project stakeholder
Client Operations Portal

Have an API or database problem?

Happy to talk through it — whether that's a new build, a slow query, or a SaaS backend that needs to hold up under real usage.