Soundararajan is known for her advocacy work against caste discrimination in the United States and India, and for her contributions to the field of media and technology justice.

[8] Soundararajan publicly revealed that she was a Dalit when she made a documentary film on caste and violence against women as a part of her college thesis at the University of California, Berkeley.

For Soundararajan, this decision had many consequences: while fellow Dalits secretly confided in her about their identity, she has also stated that she faced discrimination from all but one of the Indian professors in her campus and that they refused to advise her on projects.

[18] In May 2019, Equality Labs partnered with South Asian Americans Leading Together (SAALT), API Chaya, and the office of representative Pramila Jayapal to hold a congressional briefing on caste discrimination in the United States in Washington, DC.

During the briefing, Soundararajan and other panelists shed light on the pervasive caste discrimination experienced by Dalits and other marginalized communities in the United States.

[19] Soundararajan's advocacy group, Equality Labs told the Washington Post that more than 250 tech workers had come forward in the wake of the Cisco lawsuit, which brought caste discrimination in the US to the fore,[20][21] to report incidents of caste-based harassment.

She said that Facebook needs to strengthen its content moderation policies to address hate speech and disinformation targeted towards marginalized communities in India.

[24] In April 2020, Equality Labs published a report that Soundararajan co-authored about a coordinated social media campaign in India that was spreading anti-Muslim sentiment in relation to the COVID-19 pandemic.

The campaign involved the use of hashtags such as #coronajihad and #biojihad and was traced back to supporters of Prime Minister Narendra Modi and his Bharatiya Janata Party (BJP), as well as the Hindu nationalist paramilitary organization Rashtriya Swayamsevak Sangh (RSS).

Data from social media monitoring tools showed that the #coronajihad hashtag alone had over 249,733 interactions on Facebook between March 29 and April 3, with almost 300,000 conversations taking place on Twitter.

For instance, the Hindu nationalist movement in India, promotes ethnonationalism, exacerbates tensions across caste and religion, and perpetuates disinformation that may run counter to the beliefs of the broader South Asian community and other groups of color.

While the report reflects extreme views, Soundararajan warns that fringe movements, even those that start out with just a few followers, could grow to affect local elections and influence larger beliefs and perceptions.

[33] In 2018, She created a poster with the slogan "Smash Brahmanical Patriarchy" to draw attention to the vitriol directed towards Dalit activists on Twitter.

This poster gained significant attention when a photo of Twitter's former CEO Jack Dorsey holding the sign was circulated online, sparking controversy in India.