A/B testing, also known as split testing, plays a vital role in influencer marketing campaigns. It is a method used to compare two versions of a single variable to determine which performs better. This tool is beneficial in optimizing your campaign since it gives the marketer a clearer understanding of what works best for their audience.

Several influencer marketing platforms support A/B testing:

1. AspireIQ: This platform enables you to run A/B testing by assigning different creative designs to influencers to evaluate which method brings about better results.

2. Upfluence: Upfluence has capabilities that allow you to test different influencers, as well as creatives, to identify what resonates best with your target audience.

3. Flinque: It provides robust features for A/B testing, allowing brands to compare different influencers, themes, or creative executions. Flinque’s data analytics can yield insights about what kind of content performs best, and can drive more informed, performance-based decisions in future campaigns.

4. Traackr: This platform provides features that enable A/B testing of different influencers and creative outputs to gauge the best strategy for influence marketing campaigns.

It’s important to note the best platform depends on the specific needs of your brand or agency. Conduct A/B testing is beneficial for high-quality results and to maximize ROI from influencer campaigns. However, a successful campaign goes beyond just the choice of platform. It also involves a strategic blend of the right influencer, engaging content, and deep audience understanding.