Introducing the Carta Developer Platform

Introducing the Carta Developer Platform

Author: Reed McBride
Read time:  4 minutes
Published date:  September 6, 2023
Carta has worked for the past year with more than 25 beta partners to utilize our growing suite of APIs. Now we're expanding these capabilities.

Our customers and their service providers frequently use Carta’s platform as the central source of truth for ownership data. This data is used to generate and download reports on cap table data, portfolio holdings, employee awards, and a host of other use cases. 

To date, this experience has been less than ideal—customers and partners faced too much friction due to manual processes and unwieldy workflows. 

We knew we had to improve this, unlocking the ability to streamline operations, generate new ways of sharing information, and free up bandwidth for essential and value-creating work. 

That’s why Carta has worked for the past year to build the Carta Developer Platform and enabled more than 25 beta partners to utilize our growing suite of APIs. We are so excited to share these capabilities with an expanding list of customers and partners. 

In building the Carta Developer Platform, we were led by four guiding principles, all centered on what this could mean for our users, customers, and the ecosystem as a whole:

  1. Help our customers get more value from their Carta data

  2. Create new services to benefit Carta customers  

  3. Empower partners to serve shared customers

  4. Unlock the power of equity, everywhere

A few words on each of these principles: 

Help our customers get more value from their Carta data 

Previously, generating and downloading reports led to manual steps such as pull-and-push workflows. Business leaders would export equity awards to be matched with payroll inputs via spreadsheets, whereas today they can always see the full picture instantly using Carta and Rippling. Law firm users would log into Carta and download reports to provide advice to clients, whereas today live intel arrives in their attorney portals in real time

Carta’s APIs will reduce friction for these use cases and more, allowing customers and partners to automate their processes and build upon Carta’s infrastructure. 

Create new services to benefit Carta customers  

Through hundreds of discovery calls with customers and partners, we have learned about many potential use cases for Carta APIs. We looked for desired usage patterns with common themes that could address multiple partner verticals. 

This led to four initial Carta APIs:

  • Issuer API— Allows companies to leverage data from their full detailed cap table for uses in downstream platforms, such as HRIS providers, law firm portals, or financial services 

  • Investor API— Allows institutional investors such as VC firms to retrieve data on their own positions, and to monitor and report upon portfolio holdings 

  • Portfolio API— Allows individuals to leverage data on their holdings in Carta for downstream applications such as personal wealth management, estate planning, tax prep, option financing, or underwriting needs 

  • Launch API — Allows incorporation partners such as Stripe Atlas or law firms to onboard new companies to Carta seamlessly, in one click 

Empower partners to serve shared customers

By including partners in our discovery process from the very beginning, we identified ways to improve our overall customer experience, while also empowering our partners to better serve our shared customers on their own platforms. 

As a result, our debut developer platform partners include: 

  • next-gen estate planning services utilizing the Portfolio API to usher in a new era of estate planning (with Carta as a live source of truth for a family’s core assets)

  • leading global HRIS platforms using the Issuer API to dynamically sync employees and assess total rewards

  • Stripe Atlas and Cooley leveraging the Launch API to better serve promising new founders

  • emerging development shops helping prominent venture funds consume the Investor API for real-time portfolio monitoring 

Unlock the power of equity, everywhere 

The true promise of the Carta Developer Platform is to unlock the power of equity, everywhere. 

Private markets equity data—coming straight from the source of truth—has never been available on-demand, with real-time accuracy.

This is a step forward that will have transformative effects, from how startup employees buy their first homes, to how companies can dynamically adapt their corporate insurance coverages as they evolve, to new option financing products, to automated reporting on VC portfolio performance. 

In the coming months, the Carta Developer Platform will begin to power many additional use cases for equity data to bring new value to the world, unlocking enhanced product experiences, new economic opportunities, and greater insights and transparency across the startup ecosystem. And we’ll be listening to our community to identify additional use cases.

If you have ideas or want to see additional endpoints come online, let us know here, or write to our team at

We can’t wait to see what you build with the Carta Developer Platform. Get started below.

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Reed McBride
Author: Reed McBride
Reed McBride joined Carta in 2019 and is VP of Strategic Partnerships + Ecosystem at Carta, and an active early-stage investor. Reed started his career as a start-up attorney at Orrick, advising tech companies on billions of dollars of VC and M&A transactions. He then scaled two start-ups over five years, building new teams and leading a diverse range of functions. Reed holds a BS in Mechanical Engineering with Highest Honors from the University of Illinois and a JD from Berkeley Law, where he graduated Order of the Coif and served on the California Law Review. When he's not at work, you can usually find him on a trail with his three kids.