Hey, I'm Kanhaiya!
Java Backend Engineer
I build Spring Boot APIs, integrations and production systems that real customers use every day.
Resume 
About Me
Experience and career

I'm a Java backend engineer with about 3 years of experience building REST APIs, async jobs and third-party integrations with Spring Boot and MySQL. At Sunbase, a cloud CRM/ERP for solar installers, I owned modules from requirements to production and shipped them in 1–2 months where similar modules usually took 6–8. I was promoted within 16 months and kept the platform running as the last engineer of a 30-person team.

3 yrsprofessional experience
2–4kcalls a day through my Twilio module
~500customer accounts using modules I built
~20production issues fixed every week

Experience

Sunbase · cloud CRM/ERP for solar installers · Remote
Software Engineer 12/2025 – 10/2026
Java Backend Developer 08/2024 – 12/2025
Promoted
  • Owned backend features end to end: requirement analysis with business teams, API and MySQL schema design, implementation, release and production support.
  • Secured Spring Boot APIs with Spring Security and JWT and role-based access; added global exception handling, request validation, Swagger docs, SLF4J logging and JUnit 5 + Mockito tests.
  • Fixed about 20 production bugs and issues a week on the Java/Tomcat platform, and stayed on as the last engineer after the 30-person team was reduced.
  • Designed a schema-per-client (multi-tenant) MySQL model for the Learn module and built a Knowledge Base with an AI assistant on Llama via Ollama, used by 3,000–6,000 users.
Masai School
SDE Intern 11/2023 – 06/2024
  • Built backend APIs in Spring Boot and Python that connected the frontend to external and third-party services.
  • Turned project requirements from the product and frontend teams into backend features.

What I built at Sunbase

Company work. The code is private, so these are descriptions only.

Twilio Telephony & Campaigns

Built solo, backend and frontend, for 20 customer accounts making 2,000–4,000 calls a day: IVR with routing, recording and voicemail, browser softphone, power and predictive dialers, and SMS campaigns sending 10,000–20,000 SMS a day with @Async batching.

Spring BootSpring Data JPAMySQLTwilio

Marketing Hub & Social Media

One dashboard for GA4, Search Console, DataForSEO, Meta Ads and Google Ads through scheduled sync jobs and live API calls with Spring Cache, plus post scheduling and AI auto-replies for WhatsApp, Facebook, Instagram and LinkedIn.

Spring BootSpring CacheMeta & Google APIs

AI Voice Agents

Agents that call qualified leads and answer inbound calls on the company number, talk to the customer and book appointments into the CRM. Piloted with 2 customer accounts.

Spring BootVapi

Click-Tracking Engine

A JS tracker on JSP pages sends page, session and click events to a Spring Boot API, stored in MySQL by visitor, session and page for internal product analytics.

Spring BootMySQLJavaScript

Learn Module & Knowledge Base

Multi-tenant course platform for client teams and Sunbase master courses, plus a Knowledge Base with an AI assistant answering user questions.

Servlets/JSPMySQLLlama / Ollama

PBLib Simulation Engine

A Python library and a solar energy production simulation engine on top of it, similar in purpose to PVWatts and Aurora.

Python

Education

Full Stack Web Development
Masai School, Bengaluru
05/2022 – 05/2023
B.Com with Computer Applications
M.C.B.U., Chhatarpur, Madhya Pradesh
07/2018 – 07/2021 · 82%
Skills
Java
Java
Spring Boot
Spring Boot
Hibernate
Hibernate
MySQL
MySQL
REST API
REST APIs
Git
Git

Languages & Core

JavaPythonSQLJavaScriptOOPMultithreadingData Structures

Backend

Spring BootSpring MVCSpring SecuritySpring Data JPAHibernateJDBCREST APIsMicroservicesServletsJSP

Security & Design

JWTOAuth 2.0RBACSOLIDDesign PatternsHLD / LLD

Database & Caching

MySQLIndexingMulti-tenant Schema DesignSpring Cache

Integrations & AI

TwilioVapiWhatsAppMeta & Google Ads APIsGA4DataForSEOLlama / Ollama

Testing & Tools

JUnit 5MockitoGitGitHubPostmanSwaggerSLF4JTomcatIntelliJ IDEA

Frontend

HTMLCSSJavaScript

Soft Skills

Problem-solvingCommunicationTime ManagementAdaptabilityOwnership
Projects
Projects with public code and demos
Nicco Park booking API
Java Hibernate MySQL REST API
Nicco Park – Booking API
  • REST API for an amusement park where customers sign up, book activities and buy tickets.
  • Built with Spring Boot by a team of 5; designed and implemented the registration, booking and ticket purchase APIs.
  • Tech stack: Java, Spring Boot, Hibernate, JPQL, Lombok, MySQL.
Course Monitoring System
Java MySQL
Course Monitoring System
  • Solo project for administrators to create and manage courses, batches and course plans and track their progress.
  • Implemented authentication and input validation; delivered in 5 days.
  • Tech stack: Java, JDBC, MySQL.
Payroll and HR website
HTML CSS JavaScript
Payroll & HR Website (inspired by Gusto)
  • Website for payroll, benefits and HR software, built by a team of 5.
  • Built the Employee Benefits and People Advisory pages; users can sign up, sign in and browse the product pages.
  • Tech stack: HTML, CSS, JavaScript, localStorage.
Time tracking website
HTML CSS JavaScript
Time-Tracking Website (inspired by Toggl Track)
  • Time-tracking website for teams to log billable hours, built by a team of 5.
  • Built the sign-up and sign-in pages.
  • Tech stack: HTML, CSS, JavaScript.
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Contact Me
Get in Touch
Location
Sagar, Madhya Pradesh