SB

Sailab Banik

Sailab Banik, Software Engineer, AI Systems

Software engineer with 3+ years building production AI systems — retrieval pipelines, document intelligence, and the full-stack products that put them in front of people.

Software Engineer, AI Systems in Chennai, India

Experience

Three years at ZF Group, designing the extraction and retrieval behind an AI document platform and owning the product around it.

  • ZF Group

    Chennai, India

    1. Software Engineer II

      Oct 2024 — Present

      Build the AI side of PrimeAI, the internal document processing platform five business teams run on — annotation-driven extraction, the model-creation flow business users drive themselves, and the retrieval and prompting that decide what a model sees before it answers. Documents that cannot leave our infrastructure go to locally served models on Ollama; the problems that need a frontier model get one, and retrieval closes most of the gap between the two. I lead the frontend and own these flows end to end — interface, API, schema — alongside the role- and group-based access control the multi-team rollout needed and the CI/CD work that cut release cycle time by 40% and production hotfixes by 35%.

    2. Graduate Engineer Trainee

      Aug 2023 — Sep 2024

      The same ownership under an earlier title: interface, API, and database on a business-critical legacy platform, stabilised by clearing high-priority production bugs and cutting user-reported issues by 45%, and by reworking the operations scheduling workflows for 30% more throughput. Also ran the security hardening pass that carried the internal applications through their audits. Earned the Budding Star Award for measurable business impact in the first year.

Work

Document intelligence, retrieval, semantic caching, and distributed queues — four systems, and the numbers each one moved.

  • PrimeAI

    ZF Group, internal platform

    An AI document processing platform where business teams create their own extraction models, annotate the fields they need, and push the results straight into their workflows. I led the frontend and built role- and group-based access control from the ground up so teams with strict data rules could adopt it.

    • React
    • Redux Toolkit
    • FastAPI
    • PostgreSQL
    • Azure DevOps
    Business teams onboarded
    5+
    Less manual document review
    60%
    Operational hours saved each quarter
    2,000+
  • ContextDesk Lab

    Personal project

    A support chat built to take Redis Iris apart: every request returns an answer and, beside it, the record of how that answer was made — which memories and records reached the model, what was left out and why, and what each step cost. It exists to put a number on what a semantic cache is worth, so a question asked again in other words comes back from LangCache with the model never called.

    • Python
    • FastAPI
    • Redis Iris
    • Next.js
    • TypeScript
    • Docker
    A rephrased question answered from cache, against 4.65s through the model
    917ms
    Tokens billed on that answer, down from 576
    0
    Similarity the rephrasing matched at, against a 0.92 threshold
    1.00

    Source

  • QueueLens

    Personal project

    A job queue where FastAPI accepts work, Redis hands it to a background worker, and PostgreSQL records every job's state so nothing is lost across restarts. A Next.js dashboard shows each job moving through the queue, including failed attempts that retry with exponential backoff.

    • Python
    • FastAPI
    • Redis
    • PostgreSQL
    • Next.js
    • Docker
    Attempts per job, backing off 2s then 4s
    3
    Jobs per client every 10 seconds before a 429
    10
    Waiting jobs before the API sheds load
    100

    Source

  • Retrieval pipeline for 100+ page documents

    Personal project

    A pipeline that turns unstructured PDFs into JSON matching a schema the user defines, running entirely on local infrastructure so nothing sensitive leaves the environment. Text and tables live in separate vector stores, chunked along the document structure and reranked by a cross-encoder.

    • Python
    • LangChain
    • Qwen3
    • Chroma
    • FastAPI
    Better retrieval precision than a single-store baseline
    +40%
    Valid JSON responses, up from 75%
    100%

Credentials

Recognition for the work, and the places I went to go deeper.

  • Budding Star Award, issued by ZF Group

    Budding Star Award

    Recognition from ZF IT Global Center India for business impact in the first year.

    ZF Group, 2024

  • System Design Cohort, issued by ChaiCode

    System Design Cohort

    Distributed systems, load balancing, caching, sharding, and queues, taught hands-on.

    ChaiCode, Jun 2026

  • AI Engineer Core Track, issued by Udemy

    AI Engineer Core Track

    LLM engineering, RAG, QLoRA fine-tuning, and agent workflows across 33.5 hours.

    Udemy, May 2026

Approach

The parts of the job that aren't code, and the tools I reach for when it is.

  • I change how the team ships, not just what I ship

    Release cycle time came down 40% and production hotfixes 35% because I went after the pipeline the whole team works through rather than my own throughput. The frontend test suites went in for the same reason. Work counts when it changes how everyone ships, not how fast one person does.

  • I lead by making the reasoning visible

    Leading the frontend of PrimeAI is mostly not writing frontend. It is making a decision legible enough that the next person can pick it up, argue with it, or replace it without asking me first. Access control reached the teams with the strictest data rules because they could see exactly what it would and would not allow, not because I told them it was safe.

  • I build systems that are measurable, not just functional

    ContextDesk Lab exists because I did not want to take a semantic cache's word for it. Every request returns an execution record, a miss reports its score, and no component is ever shown as working when it was not. I build the same way at work: a claim is worth whatever the measurement behind it is worth.

Languages
  • Python
  • TypeScript
  • JavaScript
  • SQL
Interface
  • React
  • Redux Toolkit
  • Next.js
  • Tailwind CSS
Services and data
  • FastAPI
  • PostgreSQL
  • Redis
  • Chroma
AI systems
  • LangChain
  • Ollama
  • Qwen3
  • Redis Iris
Delivery
  • Docker
  • Azure DevOps
  • CI/CD
  • Git