Lead Software Engineer (ERP Modernisation)

Company Description:
Partap Singh and Sons (PSS), established in 1951, is a leading distributor of automobile spare parts across Western, Central, Northern, and Eastern India. The company partners with major manufacturers including TVS SFL, Tata Motors, Ashok Leyland, Mahindra & Mahindra, Force Motors, Maxion Wheels, Rane group companies, Schaeffler, and ZF Wabco, serving more than 18,000 customers across heavy, medium, car segments, and industrial fasteners. PSS also exports to multiple global markets. The organization aims to be the comprehensive solution provider for all aftermarket needs and relies on proprietary software to support its nationwide operational network. This focus on technology and innovation creates a dynamic environment for engineering talent looking to impact core business systems.
Role Description:
The Lead Software Engineer (ERP Modernisation) is a full-time, on-site role based in the Mumbai Metropolitan Region. The role involves leading the modernization of PSS’s proprietary ERP and related systems, including designing scalable architectures, refactoring legacy components, and implementing secure, efficient back-end services.
Why this role exists:
Partap Singh & Sons has distributed automobile spare parts since 1951. Ninety-plus branches across twenty states. Authorised distributor for Bosch, ZF, Tata Motors, Mahindra and Ashok Leyland. Fourth-generation, family-run, and one of the larger independent distribution networks in the country.
For two decades the business has run on a VB.NET WinForms ERP: 1.24 million lines of code, 18 modules, 215 screens, 1,808 Crystal Reports, on a single SQL Server 2008 box.
We have started the development on the replacement.
PSS One is Python and React, developed in-house, with a /core rulebook of 122 money-checks and an MCP server so AI agents can operate the system directly rather than screen-scrape it. It has been reconciled against real production data: 630 invoices recomputed at 99.8% accuracy, full-year double-entry integrity confirmed across all 94 branch sets, receivables ageing clean across 915 debtors. Offline billing has been proven in test. The PSS Go field app and our public sites already run on the new stack.
It is not yet live. The legacy system still holds the books. PSS One is in trials, against a copy of the data, and no branch has cut over. That is the job. Finish what is still unbuilt, then move ninety branches across without a single day's billing going wrong.
What you will own end to end:
The switchover - Two branch write-paths (goods receipt and stock adjustment) are specified but not built, and they close a branch's full daily cycle. Then clerk trials, a five-branch test, and fleet rollout across the network. You own the runbook, the pass conditions and the rollback.
The report estate - 1,808 Crystal Reports do not carry across. Establishing which ones are actually alive, and rebuilding those, is roughly forty percent of the remaining work.
The head-office console - bank reconciliation, expense posting, purchase orders, item-code approval, branch reconciliation, year-end close. Partly specified, none of it built. This is a substantial body of work sitting outside the branch rollout entirely.
GST and other taxation workflows: The existing ERP is used heavily for any GST and other tax-related filings and workflows (from procurement, to expenses, to sale). This has to be further automated and streamlined. Statutory e-invoicing still runs in the legacy system and has to move.
Branch-to-head-office data flow - Sync, offline queue, conflict resolution, reconnect rules. Move from a single on-prem server to branches syncing to a cloud brain.
The AI integration - Extending the /core rulebook and the MCP surface so agents can safely do more of the routine work.
What we are looking for:
Required
4–8 years building systems where money moves: ERP, billing, payments, accounting, logistics or supply chain. We care far more about this than about your industry
Strong Python and actively working with React. You need not be a front-end specialist, but you should be able to ship a screen end to end
Real SQL Server depth: query plans, indexing, and the ability to explain why a report takes forty seconds
Everyday, serious use of AI coding tools, together with a clear sense of where you stop trusting them. Candidates who have never used them and candidates who trust them completely will both struggle here
The ability to read twenty-year-old VB.NET without contempt.
Willingness to sit with a branch accountant in Indore and explain a change in language or a UI/screen interface she would use
B.E. / B.Tech / MCA or equivalent
Preferred, but not essential
• A legacy migration you saw through to the end, especially with a parallel run
• Nice to have: Hardware and system engineering understanding
• Understanding of how businesses operate – basic commerce and taxation knowledge. As well as a solid understanding of CRM and DMS operations.
• Crystal Reports, SSRS or similar reporting estates
• Offline-first or intermittently-connected systems
• GST e-invoicing or IRP integration
• Hindi or a regional language
How you will work
You will work directly with the CEO and leadership, who built PSS One and will be in the code processes with you.
You will also work alongside two engineers who have held the legacy system together for 20 years. They know things about this business that are written down nowhere. Part of the job is getting that knowledge out of their heads and into the new system, which requires their goodwill. If your instinct on seeing old code is to call it stupid, this is not the role for you.
How we'll hire you:
About three weeks, five stages:
1. A thirty-minute conversation with the CEO about motivation and your experience with legacy systems.
2. Ninety minutes of live pairing with the leadership and one of the existing engineers.
3. A paid take home assignment on a fully clean part of our actual pricing codebase. AI tools are explicitly permitted and expected, and we want to see how you verify what those tools give you, not whether you can generate code. We will pay you up to ₹10,000 for a submission that stands up to review, whether or not we take you forward.
4. Run a trial with an actual office clerk from one of the branches, discuss and close and feedback in loops to make sure that the operationalization is solid.
5. Any references, weighted heavily towards whether you finish what you start.
Compensation and logistics:
• ₹110,000 per month fixed, plus quarterly performance bonuses. PF and gratuity as part of overall compensation
• Mumbai, on-site, with travel to branches during the rollout
• Tell us your notice period. We will consider a buy out for the right teammate
To apply:
Apply through LinkedIn and/or write to hr@pssao.com with two things:
1. One paragraph on the hardest bug you have found where the system did not crash, it just produced a wrong number.
2. Your notice period, and whether it is negotiable
We read every application and reply either way. Good luck!

Work arrangement
No