How to Integrate Third-Party APIs Into Your Marketo Campaigns

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With its comprehensive functionality and real-time data, Marketo is the leading marketing automation platform. However, it doesn't integrate with every application out there which means that the full value of the platform is often not realised by many users. If you need data from a third-party API, here's how to get it into your Marketo campaigns, ensuing that you successfully integrate third-party APIs.

How Do Third-Party Integrations Work?

As a platform, Marketo exposes a REST API that developers can use to remotely execute various system capabilities. Examples include importing leads in bulk and creating new programs. With countless configuration options, Marketo also empowers users to gain very fine-tuned control over the Marketo instances they're working with.

You'll find that Marketo's APIs fall into one of two broad categories: Asset APIs and Lead Database APIs. The former enables interactions with records in the workflow and marketing collateral, while the latter enables you to retrieve and interact with person records, opportunities, and companies. 

Do you have SOAP APIs that you need to convert to REST APIs? That's just one more thing that DreamFactory makes easy. Learn more here.

API Limits for the Marketo Platform

Marketo offers its own extensive guide for developers interested in setting up third-party API integrations. In this guide, it begins by summarizing the API limits, which include:

    • A daily quote of up to 50,000 API calls per day. The number resets at 12:00AM CST. You can ask your account manager if you need a higher daily quota.

    • A rate limit of 100 calls per 20 seconds for each instance.

    • A maximum of 10 concurrent API calls.

Besides the above, you'll also note a bulk import file size limit of 10MB, a SOAP max batch size of 300 records, and a limit of two executing bulk extract jobs with up to 10 queued. If you're concerned with limits, you can always ask your Marketo account manager if they can be increased for your account.

Best Practices for Marketo's Third-Party API Integrations

When you're setting up third-party API integrations, there are a number of established best practices you should follow. Below, we'll briefly discuss the concepts of batching, latency, caching and shared limits as core components of any strategy aimed at improving how to integrate third-party APIs.


Use the bulk and batch tools when appropriate and only use single result/record calls when absolutely necessary. Help improve the performance of your integrations by grouping records into fewer transactions every time you perform an update or insert. When you retrieve records for submission, always aggregate them before submitting, rather than submitting requests for each change after the fact. 


How much latency can your applications tolerate? This defines the longest amount of time that can pass before submitting an API call. Knowing this number will help inform many of the integration design decisions as Marketo provides different configuration options and methods suitable for various latency ranges.

For instance, if you require a real-time integration that notifies a sales professional when someone signs up for a free trial, single batches may be submitted if immediate follow-up is necessary. However, most use cases do not require such expediency, so queuing and batching calls can handle things more efficiently. 


Partitions, activity types, and results from "Describe" operations are generally cached for a day. Caching other assets, such as emails and folders, is also appropriate for some applications, so explore your caching options and choose them accordingly. 

Shared Limits

You should always avoid concurrent API calls unless there's a direct benefit for your application. This is because each Marketo instance has a limit of 10 concurrently executing calls. Like the daily quote and rate limits, the concurrency limit is also shared across the instance, so don't assume your application will be the only one consuming this limit.

The best practice here is to always assume your application is going to compete with other apps for quota, rate, and concurrency resources and set conservative limits accordingly. For Marketo's rate limit, it suggests third-party API integrations limit utilization to no more than 50 per 20 seconds to ensure fair usage by all API integrations. 

Make The Most of Your APIs

Third-party API integrations are powerful, especially when you're working with an already incredible platform like Marketo. However, managing all of your APIs, re-using them within a microservices environment, and staying on top of all the documentation associated with them can all get very complex.

Want to know more about how you can effectively and quickly integrate third-party APIs? DreamFactory's low-code platform makes API management a breeze. Get hands on with features designed to make designing and maintaining an effective API strategy simple. Start your free trial!

Related reading:

10 API Developer Mistakes to Avoid