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APIs are a game changer. They let you save costs in building an entire infrastructure from scratch and reach the market much faster. 

You’ve launched an innovative investing business and intend to build a product that solves your customers’ problems. But building a product from the ground up is costly and complex. 

This is where APIs come in. Let’s have a look at how they can ease your product-building process:

Integrating with an API allows you to customise your users' investing experience and build your platform to align with your specific requirements. 

To learn more about the benefits of APIs, check out this article - How APIs are transforming the wealth management industry.

Selecting the right API 

The first step in building an investing app on top of an API is selecting a suitable one. Here’s a checklist that you can use- 

Data Source 

You should pick an API that pulls the information you need from a legal and trusted source. 

API Calls 

Many data vendors limit the number of calls/requests you can make, so you should consider your desired frequency and quote accordingly.


Higher latency APIs deliver live data to you without much delay and is helpful if your app involves making quick decisions.


You should select a provider with a sandbox environment to test their APIs before you commit to using them. 

Other questions to consider 

  • How is the API priced?
  • Is the API secure from data breaches and cyber-attacks? 
  • Can it handle sudden spikes in incoming traffic?

Performance and security are must-have features in your choice of API. If it is slow, buggy or has security issues, it will affect your product and customer experience. 

How to build an investing product from APIs 

After you’ve selected a suitable API for your business, you’ll need to register and authenticate your business with the API provider. We’re using WealthKernel as an example; other APIs could differ in terms of endpoints and authentication.

Here’s a step-by-step guide with examples that’ll help you understand the process - 

Client Key and Client Secret 

You’ll have to register with your selected API provider and get the client key/client ID and client secret.

The Client Key/ID is the key associated with your application. The Client Secret is the key used to sign requests on behalf of your application.

You’d then have to log in using the API Keys. 

Access Token

You’ll get an access token post authentication. An access token is a key used to make requests on behalf of your user account. 

Here’s an example of how to retrieve an access token -

Creating a Party

You can now create your first party and add the party's address and bank account details. 

Now you can create an account (ISA, GIA, etc.) for the party. 

Creating a Portfolio 

Finally, you’ll have to create a portfolio within the account and fund your first portfolio by creating a deposit.

Your customers will need to transfer the amount to the API provider, which will then be matched with the deposit and funded in the portfolio. 

You can now see your portfolio transactions. Here’s a short example that returns a list of transactions in a portfolio- 

curl --request GET \

  --url https://stoplight.io/mocks/wealthkernel/api/14767227/transactions \

  --header 'Accept-Version: 2021-05-17' \

  --header 'Content-Type: application/json'

And here’s a sample response - 



    "portfolioId": "prt-32q2deogu225ps",

    "isin": "GB0030029069",

    "type": "Buy",

    "status": "Settled",

    "price": {

      "currency": "GBP",

      "amount": 0.8628


    "quantity": 91.216,

    "consideration": {

      "currency": "GBP",

      "amount": 78.7


    "charges": {

      "currency": "GBP",

      "amount": 0


    "date": "2019-10-08",

    "timestamp": "2019-10-08T13:55:16.4237925Z",

    "settledOn": "2019-10-08",

    "updatedAt": "2019-10-08T13:55:16.4237925Z",

    "bookCost": null,

    "id": "txn-32q2m7mwn264vg"



Using an API will drive down costs and save time, giving you a significant competitive edge. 

With many financial players releasing their APIs, it is easy to integrate and create unique functionalities for your business. 

“Externally, using third-party APIs will allow you to focus on just your product by eliminating the complexity and time needed to build everything from scratch. Internally, building your own APIs will give you the flexibility and agility to help you build at speed and at scale,” -  Niall Maloney, Senior Developer at WealthKernel.  

Have some questions? Get in touch with us at marketing@wealthkernel.com.