API Integration Services India: How to Vet Vendors

Most Indian B2B teams do not wake up wanting "API integration services." They wake up because Shopify orders are being retyped into Tally, or a client wants invoice data pushed into their SAP portal, or the GST e-invoice IRN has to reach three systems without a human copy-pasting JSON. The vendor search usually starts two weeks before go-live — exactly when you have the least leverage to ask good questions.

What API integration services in India should actually cover

The phrase covers everything from "connect Razorpay to Zoho Books" to "build a middleware layer across six systems." Get your scope into one of these buckets before comparing quotes:

• Point-to-point sync. Two systems, one or both directions. Example: Shopify order to Tally sales voucher, with GST tax lines mapped.
• Middleware. A normalising layer between ERP, CRM, payments and logistics. More work upfront, cheaper per new system later.
• Event and webhook handling. Real-time triggers like payment captured or shipment delivered. Needs queues, retries and idempotency keys.
• Migration and reconciliation. One-time backfill plus a daily job that flags mismatches.

A vendor quoting a flat rate without asking which bucket you are in is guessing. Scope also decides the integration architecture: a queue like RabbitMQ, a scheduler like Airflow, or a small service on a cloud VM.

Questions to ask before you sign

Ask these on the first call, not after the proposal.

• Who writes the mapping document? You want a field-by-field sheet: source field, target field, transform, owner. If it is not in the contract, it gets discovered during testing.
• How do you handle secrets? OAuth2 refresh tokens, API keys and IP whitelists need a home — a vault or encrypted environment variables, never a spreadsheet.
• What happens when the other API rate-limits you? Ask for their backoff, retry and queue design. "We will just call it again" is not a production answer.
• Is the integration idempotent? If the same webhook fires twice, do you get two invoices or one? This prevents most duplicate-entry incidents.
• How will we know it broke? Alerts to email, Slack or WhatsApp, plus a dashboard of failed messages. Silent failures are the expensive kind.
• Who owns code and docs at handover? Repo access, environment variables, deployment steps, runbook. Vague answers mean you are renting, not buying.
• How does this fit the DPDP Act? If names, phone numbers or GSTINs move between systems, ask where data lives, who can access it, and the retention policy.
• What is the test scope? Sandbox credentials, staging, and a defined set of test cases. "We will test in production" is not a plan.

A worked example: 14,000 orders a month

A mid-market distributor in Bhiwandi pushed about 14,000 orders a month from a custom storefront into Tally and a logistics partner. Three staff spent roughly three hours a day reconciling orders, e-way bill numbers and shipping charges — about 65 person-hours a month.

The scope was modest: one inbound webhook, a 22-field mapping sheet, GST rate lookup by HSN code, a retry queue, and a daily reconciliation report. Build time was four weeks with one developer and part-time QA. Reconciliation dropped to a 20-minute morning check.

The vendor was not the cheapest quote. It was the one that showed a mapping sheet and an error dashboard before signing. The items that save time are rarely the API calls — they are the mapping, retries, alerts and reconciliation report nobody puts in the sales deck.

Red flags and pricing models

• No mapping document in the proposal. You will pay for that discovery later at change-request rates.
• Hourly billing with no milestones. You cannot tell if you are 40% or 90% done.
• No mention of rate limits, retries or idempotency. These are core to integration work, not extras.
• No handover plan. Ask what happens if the vendor disappears in month seven.

In our experience, Indian SMB integration projects often land here: a simple two-system sync runs ₹40,000–₹1.5 lakh; multi-system middleware with queues and monitoring runs ₹3–8 lakh; support retainers sit around ₹25,000–₹75,000 a month depending on volume. These are indicative, not a rate card. Hosting, third-party licences and the other side's API fees are usually extra.

If the integration sits alongside a customer portal or dashboard, review how web platforms tie front end, APIs and reporting together. For queues, cron jobs, monitoring and deployments, cloud setup covers what stops a nightly sync becoming a morning fire.

Where to start

Write a one-page scope before you talk to anyone: systems involved, data direction, fields, daily volume, who owns each API, and what "done" looks like. Send it to two or three vendors and compare how they respond. Maysan Labs builds API integrations, web platforms and internal tools for Indian SMBs and mid-market teams; the first conversation is usually about that one-page scope, not a proposal.