Custom ERP Development in India: Modules, Cost, Timeline

Description

Service Custom ERP development: one system for orders, stock, purchase and accounts

A custom ERP is one database for sales orders, purchase, stock, production and accounts, written around the way your business already works. WavX builds it one module at a time, starting with the process that costs you most, and connects it to GST e-invoicing and Tally where needed. If a standard product fits your process, buy that instead; this page says when.

Tell us what you need built Last updated 2 October 2026

What a custom ERP is, and when to build one

An ERP is one database for the whole operation. A sales order entered once reserves stock, raises a dispatch note, becomes a GST invoice and lands in the customer's ledger, without anyone typing it again. A custom ERP is that system written around your process, instead of a vendor's process configured to resemble yours.

Building one is the right call in three situations:

Your process is the business. A job-work cycle, a pricing rule, a quality hold or a commission structure that no standard product models without heavy modification.

You already tried a product. You pay for every change, staff keep a parallel spreadsheet, and the reports the owner wants still come from Excel.

The ERP must talk to something unusual. A weighbridge, machines on the shop floor, a dealer app, a marketplace, or a legacy system that has to stay.

If none of these is true, a ready product is cheaper and faster. The last section of this page says which one to look at.

Modules a custom ERP usually contains

Nobody should build all of these at once. The table is a map of what an ERP can cover, so you can mark what your first phase needs.

Module

What it handles

The part that is specific to India

Sales and orders

Quotations, sales orders, price lists, credit limits, dispatch

GST tax invoice with HSN or SAC codes; e-invoice reporting where it applies

Purchase and vendors

Requisitions, purchase orders, goods receipt, vendor bills, approvals

Vendor GSTIN on every bill; a purchase register in the layout your accountant uses

Inventory and warehouse

Stock by location, batches and serial numbers, reorder levels, transfers

E-way bill details for consignments that need one

Production and job work

Bills of material, work orders, material issue, wastage, sub-contracting

Challans for material sent to and received from job workers

Accounts

Receivables, payables, ledgers, bank reconciliation

Either full books in the ERP, or a sync to Tally

HR and payroll

Attendance, leave, salary runs

Attendance devices; salary structures as your payroll consultant defines them

Sales pipeline

Enquiries, follow-ups, quotations

WhatsApp follow-ups logged against the customer

Reports and dashboards

Daily sales, receivable ageing, stock valuation, margin by product

Reports split by GSTIN if you hold more than one registration

Roles, approvals, audit log

Who can see, edit and approve; a record of every change

Approval limits by rupee value

Most first phases are two or three rows of this table. The others are added once the first is in daily use.

GST, Tally and WhatsApp: the India-specific parts

These are the parts that make an ERP for an Indian business different from a generic one. Each should be settled in scoping, not discovered in testing.

E-invoicing. Since 1 August 2023, e-invoicing applies to taxpayers with aggregate turnover exceeding ₹5 crore. B2B invoices are reported to the Invoice Registration Portal, which returns an Invoice Reference Number (IRN), a digitally signed invoice and a QR code. An ERP for a business above that line has to do this from the invoice screen, handle rejections, and print the IRN and QR code on the invoice. Below the line, the invoice structure should still be built so that switching e-invoicing on later is a setting and not a rewrite. Your chartered accountant will confirm whether it applies to you. See GST e-invoicing integration .

E-way bills. Under Rule 138 of the CGST Rules, a registered person who causes movement of goods of consignment value above ₹50,000 has to furnish the consignment details in Part A of an e-way bill, and Part B carries the transport details. The dispatch screen should collect both, so that the person loading the vehicle is not typing the invoice again on a government portal.

Tally. Decide early whether the ERP replaces Tally or feeds it. If your accountant will keep working in Tally, the ERP should push sales, purchase, receipt and payment vouchers into it and leave the books there. TallyPrime exchanges data with other applications in XML and in JSON, and JSON is built in from TallyPrime 7.0. The mechanics are on the Tally integration page.

WhatsApp. Order confirmations, dispatch updates and payment reminders can go out through the WhatsApp Business Platform as template messages. As of October 2026, Meta charges for these per message, by template category, so the ERP should send them deliberately and not on every status change.

What to decide before building

These decisions change the scope more than any feature list does.

Which process goes first. Pick the one that costs you money every week: stock that does not match, invoices raised late, purchases made without approval. That is phase one.

Where the books live. In the ERP, or in Tally with a sync. This decides whether an accounts module is built at all.

Who cleans the master data. Item codes, units, customer and vendor lists, opening stock and opening balances. A new ERP loaded with a messy item master produces messy reports faster.

Who approves what. Write down the approval limits as they really operate, not as the organisation chart says.

Where it runs. Cloud hosting suits most businesses. A factory with an unreliable connection may need screens that keep working offline and sync later, which adds cost.

How you switch. Run old and new side by side for one full billing cycle, or cut over on the first day of a month. Decide before the build, because it shapes the data migration.

The five reports the owner reads. Build those first. Everything else can wait.

How WavX builds an ERP

WavX builds custom ERP systems as web applications, typically on React or Next.js with Node.js or Python and a PostgreSQL database, hosted on AWS, Google Cloud or Azure in an account your company owns.

The work runs in phases, not as one large delivery.

Process mapping. WavX talks to the people who do the work, records each document and handover, and writes the flow back to you in plain language for correction.

Data model and first module. The item, customer, vendor and tax structure is fixed first, because every later module depends on it. Then the phase-one module is built and shown to you as working software while it is being made.

Migration and parallel run. Masters and opening balances are imported, and staff use the new system alongside the old one until the numbers match.

Next modules. Each further module is scoped and quoted on its own, using what the first phase taught both sides.

Role-based access and an audit log are part of every build. You own the source code and the intellectual property. The engagement can be fixed price, time and materials, or a mix of the two, and is quoted after a free consultation.

What it costs: a planning range

WavX publishes its cost model in the software cost estimator . The figures below are worked from that model. They are planning ranges for budgeting, not quotes.

Scope

Model inputs

Subtotal

Planning range

One module for one team, such as purchase with approvals

Internal tool base ₹2,00,000 + auth and roles ₹60,000 + exports and reporting ₹50,000

₹3,10,000

₹2,63,500 to ₹3,87,500

Core ERP for a small business

ERP/CRM base ₹9,00,000 + auth and roles ₹60,000 + third-party integrations ₹60,000 + analytics dashboard ₹80,000 + exports and reporting ₹50,000

₹11,50,000

₹9,77,500 to ₹14,37,500

The same ERP at the model's "growing" scale

Subtotal above × 1.3

₹14,95,000

₹12,70,750 to ₹18,68,750

Assumptions: standard design, small scale unless stated, and the model's spread of 15% below to 25% above the subtotal. Select the same options in the estimator to reproduce the figures.

Not in these figures: cleaning and migrating old data beyond a straightforward import, hosting, fees charged by an e-invoicing or messaging provider, and a companion mobile app, which the model prices at ₹2,00,000. After launch, plan for maintenance of 15% to 25% of the build cost per year, the band published in the maintenance cost guide .

Existing WavX posts print their own figures for narrower and wider scopes. For a module-by-module breakdown, read ERP software cost in India .

Timeline

The cost model places a build with a subtotal between ₹3,00,000 and ₹6,00,000 in its 6 to 10 week band and anything larger in its 10 to 16 week band. WavX's stated typical timeline for complex ERP and CRM platforms is 3 to 6 months. Use the longer figure if the scope includes several modules, data migration and a parallel run.

What slows an ERP is rarely the code. It is master data that is not ready, and approvers who are not available to test.

When an off-the-shelf ERP is the better choice

Buy a product if your process is ordinary for your industry. That is no criticism of the business. It means someone has already written your software.

Your situation

Look at first

Why

Trading or services firm that needs accounts, GST billing and basic stock

TallyPrime, Zoho Books

TallyPrime covers accounting, inventory, e-invoice and e-way bill generation and GST returns. Zoho Books is GST-compliant accounting software with e-invoices and e-way bills, and has a free plan for businesses that are starting out.

Manufacturer or distributor with a standard flow and someone technical on the team

ERPNext, Odoo

ERPNext is open source and covers accounting, stock, manufacturing, CRM and HR; its India Compliance app adds GST, e-invoicing and e-way bills. Odoo is a suite of business apps with a free open-source Community edition and a paid Enterprise edition.

Mid-sized company whose auditors or parent company expect a recognised ERP

Microsoft Dynamics 365 Business Central

Microsoft positions it as ERP for small and midsize businesses.

Product descriptions are as each vendor states them in October 2026. The comparison in ERPNext vs custom ERP goes further, and ERP for small business in India covers whether you need an ERP at all.

A middle path is often the sensible one: keep accounts in a product, and build only the part that is specific to you, such as the production flow, dealer ordering or the pricing engine, connected to the product through an integration.

Custom ERP development is one part of custom software and business systems at WavX.

Frequently asked questions

How much does custom ERP development cost in India?

It depends on how many modules are in the first phase. The WavX cost model gives a planning range of about ₹2.6 lakh to ₹3.9 lakh for a single module for one team, and about ₹9.8 lakh to ₹14.4 lakh for a core ERP for a small business. These are planning ranges from the software cost estimator on this site, not quotes. A quote follows scoping.

How long does it take to build an ERP?

The cost model puts a single module in its 6 to 10 week band and a full core ERP in its 10 to 16 week band. Our stated typical timeline for complex ERP and CRM platforms is 3 to 6 months. Plan on the longer figure if the scope includes several modules, data migration and a parallel run with your old system.

Can a custom ERP work with Tally?

Yes. If your accountant will keep the books in Tally, the ERP handles operations and pushes sales, purchase, receipt and payment entries into Tally. TallyPrime exchanges data with other applications in XML and JSON. The alternative is to keep full accounts inside the ERP, which is a larger build.

Do we need GST e-invoicing built into the ERP?

If your aggregate turnover has crossed ₹5 crore, e-invoicing applies to your B2B invoices and the ERP should report them and print the IRN and QR code from the invoice screen. If you are below that, we still structure invoices so that e-invoicing can be switched on later. Ask your chartered accountant to confirm whether it applies to you.

Should we use ERPNext or Odoo instead of building?

If your process is standard for your industry, usually yes. Both are mature products with accounting, stock, manufacturing and CRM modules. Build custom when the product would need so much modification that you end up maintaining custom code anyway, or when the part that matters most to you is something no product models.

Who owns the ERP once it is built?

You do. The source code and intellectual property of what we build for you belong to your company, and the system runs in hosting accounts in your company's name.

Sources

Notification No. 10/2023-Central Tax: e-invoicing for aggregate turnover exceeding ₹5 crore from 1 August 2023 (GST Council) · read 2 October 2026

e-Invoice system: IRP, IRN, signed invoice and QR code (GST e-invoice portal) · read 2 October 2026

Electronic Way Bill in GST: Rule 138, consignment value above ₹50,000, Part A and Part B (CBIC) · read 2 October 2026

Integration with TallyPrime: XML, JSON, ODBC and TDL (Tally Solutions) · read 2 October 2026

TallyPrime integration using JSON: native JSON from TallyPrime 7.0 (Tally Solutions) · read 2 October 2026

WhatsApp Business Platform pricing: per-message pricing and template categories (Meta) · read 2 October 2026

TallyPrime product page (Tally Solutions) · read 2 October 2026

Zoho Books for India (Zoho) · read 2 October 2026

ERPNext product page (Frappe) · read 2 October 2026

ERPNext documentation: India Compliance app (Frappe) · read 2 October 2026

Odoo home page: Community and Enterprise editions (Odoo) · read 2 October 2026

Dynamics 365 Business Central (Microsoft) · read 2 October 2026

Related

Custom ERP software development in India: the full guide

How to build an ERP system

Custom inventory management software

Custom CRM development

HRMS and payroll software

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