A single website API integration typically costs between ₹15,000 and ₹1,50,000. The exact number depends on the service you’re connecting and how much custom logic it needs. A basic payment gateway sits at the low end. A two-way ERP sync sits at the high end. This guide explains what drives that cost. Use it to scope a request properly before asking an agency for a quote.
What Counts as an API Integration, Exactly
An API integration connects your website to an external service. Data flows automatically, without anyone copying information by hand. A payment gateway checking out a customer counts. A shipping service calculating delivery cost counts. A CRM logging every new lead counts too. Each integration saves manual work. Each one also adds a dependency your site now relies on.
Payment Gateway Integration
Most Indian payment gateways provide ready plugins for WordPress and WooCommerce. Razorpay, PayU, and Cashfree all fall into this category. Basic setup with a standard checkout flow costs ₹15,000 to ₹30,000. Custom checkout flows push that number higher. Subscription billing and multi-currency support do too. Both need custom code beyond the plugin’s default behavior.
CRM Integration
Connecting a website’s contact forms to a CRM ranges widely in cost. Zoho, HubSpot, and Salesforce are the most common targets. A simple one-way sync, where form submissions create a CRM record, costs ₹20,000 to ₹40,000. A two-way sync costs considerably more. CRM updates then reflect back on the website, showing order status or account details. That reverse flow needs ongoing error handling for moments when one system goes temporarily unreachable.
Shipping and Logistics Integration
An eCommerce store connecting to Shiprocket, Delhivery, or a similar platform needs two things. It needs real-time rate calculation at checkout. It needs automated label generation after each order. This typically runs ₹25,000 to ₹60,000. The final number depends on how many shipping rules and pin code exceptions the business must handle.
ERP Integration
Connecting a website to an ERP system is the most expensive category, and the most variable. Tally, SAP Business One, and custom ERPs all fall here. Costs start around ₹75,000. They can exceed ₹2,00,000 for complex cases. Several variables drive that range. How modern is the ERP’s own API? Does inventory need to sync in near real-time? How many business rules, tax handling, multi-warehouse stock, pricing tiers, need to travel across the integration correctly?
Third-Party Booking Systems
A business embedding a booking or appointment system usually pays ₹20,000 to ₹50,000 for integration. Clinics, salons, and rental services all use this model. The range depends on one main factor: does the booking data need to sync with a separate calendar or staff tool, or does it stay self-contained within the widget?
What Actually Drives the Cost Up or Down
API Documentation Quality
A well-documented, modern REST API takes far less development time than a poorly documented one. Some older or enterprise systems expose clunky SOAP APIs. Others offer no real documentation at all. Developers spend real hours just figuring out how the system behaves before writing any integration code.
Authentication Complexity
A simple API key check adds almost no cost. OAuth flows add real development time. Token refresh logic adds more. Per-user authentication needs to keep working reliably over months and years, not just on launch day, and that reliability requirement is where the cost comes from.
Data Mapping
Your website’s data structure rarely matches an external system’s structure exactly. Someone has to write logic that translates between the two. A product with 20 custom fields adds mapping work. A customer record with fields the other system doesn’t recognize adds more. None of this shows up in a demo. All of it shows up in the final invoice.
Ongoing Maintenance
APIs change over time. A payment gateway updates its SDK. A shipping partner changes its rate structure without much notice. Budget for ongoing maintenance. Expect roughly 10 to 15% of the original integration cost per year, just to keep the connection working as the external service evolves.
A retail client of ours needed to integrate a legacy inventory system. That system exposed no real API at all, only a nightly CSV export. A live, real-time integration would have meant building custom infrastructure around a system never designed for it. Instead, we built a scheduled sync that ran every hour. It cost a fraction of a real-time build. It also met the client’s actual requirement: stock counts accurate within an hour, not to the second.
Free vs Paid Third-Party Services Behind the Integration
The integration cost you pay a developer is often separate from the third-party service’s own fees. Some payment gateways charge only a transaction percentage, with no monthly fee. Others, especially CRMs and ERPs, charge a recurring subscription on top of any integration work. Ask early which model applies, since a “cheap” integration into an expensive subscription service can cost more in year one than a pricier integration into a free-tier tool.
How to Scope a Request Before Asking for a Quote
Answer three questions before contacting an agency. What system are you connecting to, and does it have public API documentation? Does data need to flow one way or both ways? How real-time does the sync actually need to be: hourly, daily, or instant? Vague requests like “connect our website to our CRM” produce vague quotes. A specific brief produces a specific, comparable price.
Signs You’re Being Overcharged for an Integration
A few warning signs suggest an inflated quote. A flat price with no breakdown of hours or scope is one. A vague answer when you ask what happens if the external API changes is another. Watch for a quote that treats every integration as equally complex, since a standard Razorpay setup should never cost the same as a custom ERP sync. Ask for a rough hour estimate alongside the price. A developer who can explain where the hours go usually understands the work better than one who can’t.
Also ask directly whether the quote includes testing. Some agencies quote only the build, then bill separately for testing and bug fixes after launch. That split can double your real cost without ever appearing in the original number.
Testing an Integration Before It Goes Live
Every integration needs testing in a sandbox or staging environment first, never directly on your live site. Most payment gateways, CRMs, and shipping platforms provide test credentials specifically for this. Test the normal path first: a successful payment, a successful CRM record creation, a successful shipping rate lookup. Then test the failure paths. What happens when a payment fails? What happens when the external API times out? A site that only handles the happy path breaks the first time something goes wrong in production, often during a busy sales period when it matters most.
Budget testing time as part of the integration cost, not as an afterthought. A rushed integration that skips proper failure-path testing tends to generate support tickets and lost orders within the first month of going live.
Who Should Own the Integration Long-Term
Decide upfront who monitors the integration after launch. Some agencies include a monitoring period, typically 30 to 90 days, in the original quote. After that window, someone needs to own it: your internal team, a maintenance retainer with the original developer, or a general website support contract. An integration with no clear owner tends to fail silently. Nobody notices a broken payment sync or a stalled CRM feed until a customer complains or a sales report looks wrong weeks later.
Ask this question before the project starts, not after something breaks. A clear ownership answer, written into the original agreement, avoids a scramble later when an API update quietly stops the integration from working.
Bundling Multiple Integrations Into One Project
Businesses often need more than one integration at once, a payment gateway plus a shipping service plus a CRM, for example. Bundling these into one project usually costs less than commissioning them separately, since a developer only sets up the local environment, testing process, and staging site once instead of three times. Ask for a bundled quote if you know you need several integrations within the same few months, rather than spacing them out as separate small projects with repeated setup overhead each time.
Frequently Asked Questions
Can I integrate an API myself without a developer?
Some integrations need minimal technical work, like a standard payment gateway with an official plugin. Custom logic, data mapping, or two-way sync generally need a developer to build and test properly.
What happens if the external API goes down?
A well-built integration handles this gracefully. It queues failed requests and retries later, instead of losing data or crashing the site. Ask your developer how they handle API downtime before the integration goes live.
Do I need to pay for the third-party API itself, separate from the integration cost?
Often, yes. Many CRMs, ERPs, and shipping platforms charge their own subscription or per-call fees. That’s separate from what you pay a developer to build the connection.
How long does a typical integration take to build?
A standard payment gateway or booking system integration takes one to two weeks. CRM and ERP integrations with custom data mapping typically take three to six weeks.
If you’re planning an integration and want a quote based on your actual systems rather than a generic estimate, see what our website development services include, or get in touch with the specifics of what you’re connecting.
