API Security for Apps and Integrations

API security needs its own plan because APIs have no page to look at. Someone can pull or change data through an API without ever opening your website.

Modern businesses connect many tools. Your website sends leads to a CRM, your store sends orders to a shipping tool, and your mobile app talks to a server. Each of these links uses an API. If an API is open or weak, someone can pull data or make changes without ever touching your website front end.

API problems are easy to miss because there is no page to look at. That is why they need a planned review.

This matters for small businesses too, not just big tech firms. A small online store may have APIs for payments, shipping, SMS, WhatsApp messages, CRM sync and accounting. Each one has a key, and each key is a way in. If a developer copied a key into a public code folder or a shared document, anyone who finds it may be able to use it. A short review often finds keys that should have been changed long ago.

The most common API risks are leaked keys, weak access checks, responses with too much data, no rate limits, poor logging and old versions left live.

These risks match well-known lists such as the OWASP API Security Top 10. In small businesses, the first two, leaked keys and weak access checks, cause most real problems.

Short-lived tokens and OAuth are usually safer than a single long-lived API key, because they expire and can be limited to certain actions. Keys are fine for server-to-server use if they are kept secret and limited.

What matters more than the method

Whatever method you use, the server must check what each caller is allowed to do. A valid token should never mean full access. Each user or system should reach only its own data, and only the actions it needs.

We secure APIs in six steps: list every API, check logins, check access rules, add limits and input checks, protect secrets, and set up logging and alerts.

1. 1

   List every API

   Your own APIs and the third-party APIs you call, with what data each one handles.

2. 2

   Check authentication

   Tokens, keys and who can use each endpoint.

3. 3

   Check authorisation

   Each user and system should only reach its own data.

4. 4

   Add limits and validation

   Rate limits, input checks and safe error messages.

5. 5

   Protect secrets

   Move keys to secure settings, rotate old keys and limit their permissions.

6. 6

   Log and monitor

   Record API use and alert on unusual spikes. See security monitoring.

For a few APIs, this work often takes one to two weeks. Larger systems with many integrations take longer. Fixes are ranked by risk, so the most exposed endpoints are handled first.

Give each third-party key the least access it needs, store it in server settings, verify webhook signatures and change keys on a schedule and when staff or vendors leave.

Many security problems come from integrations rather than your own code. For example, a payment, SMS, WhatsApp or CRM key with full access may be shared with several developers over the years. We review these keys, reduce their permissions to the minimum, and set a plan to rotate them.

Our parent team builds CRM, WhatsApp marketing and other integrations every day, so we understand how these connections are set up in real projects. For custom app code, see web application security.

Integration safety checklist

• Each key has only the permissions it needs, such as read-only where possible
• Keys live in server settings, never in website or mobile app code
• Payment and order webhooks check the signature before acting
• Separate keys for testing and live use
• A list of who has access to each key, updated when people leave
• Old and unused keys are deleted, not just ignored

Online stores have many such integrations. Our ecommerce security service covers checkout, payment and order tools in more detail.

Revoke and replace the leaked key at once, update every system that uses it, then check logs for misuse. Do this before anything else.

1. Revoke the key in the provider's dashboard and create a new one
2. Update the new key in server settings for each app that uses it
3. Check usage logs for calls you do not recognise
4. Check for unexpected charges, messages sent or data exported
5. Find how it leaked, such as a public code folder or shared document, and close that gap
6. Limit the new key's permissions to the minimum

If customer data may have been exposed, also review your duties under India's data protection rules with a legal advisor. Our data security service helps with the technical clean-up. For urgent cases, our 24x7 emergency support can help straight away.

API security cost depends on how many APIs and integrations you have, access to code and docs, and whether you want ongoing monitoring. You get a clear quote after a free call.

• Number of APIs and endpoints
• Number of third-party integrations
• Access to code and documentation
• Need for ongoing monitoring

You get a clear quote after a free call.

More mistakes we often see

• Putting a secret key inside a mobile app, where anyone can extract it
• Using the same key for testing and the live system
• Sending full customer records when the app only shows a name
• Returning detailed error messages that reveal how the system works
• Keeping old API versions live after the new one launches

For the app around the API, see web application security. If your APIs run on cloud servers, our cloud security services cover the server and account settings too.

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