Our Tech Stack

John Tylwalk
Oct 3, 2017 · 5 min read

We’re building the Financial Platform for the world. We have over $750 billion worth of assets on our platform that translates to 1.4 million nodes and 6.3 million edges in our financial graph from 268 thousand accounts. Every day we process hundreds of gigabytes of data from a few hundred sources and our API server handles 2.5 million requests every day for thousands of users. With our , these numbers are also growing rapidly.

In this post, we will go through the tech stack that we’ve used so far to build Addepar and handle these challenges.

Our Tech Choice Philosophy

At Addepar, we use the right tool for the job. We would never choose a technology, library, or language just because it’s sexy.

We’re careful and deliberate about introducing new technologies. Supporting multiple tools is expensive. We consider everything from the ongoing maintenance and operational costs to the effort required to develop and implement best practices, code standards, and tooling across many languages. Consequently, you can see from the description below that, for the most part, we try to keep the stack as simple as possible, but no simpler, for our problem domain.

Current Tech Stack


We use . We incorporate many AWS features into our system architecture, but we primarily stick to the generic ones (like software-defined networking and elastic scaling of resources) to avoid relying on Platform as a Service offerings for our mission-critical systems. Doing so allows us to be provider-agnostic while leveraging AWS Infrastructure as a Service solutions.


The Addepar platform is a sophisticated, service-oriented system that’s capable of processing hundreds of thousands of financial accounts daily. We have a robust data pipeline for ingesting and transforming custodial and vendor data input, a normalization layer that enforces strong guarantees about our financial data, and a computational stack that drives our realtime web-based analysis views and comprehensive report generation tools.

Languages, Build Tools & Configuration Management

For simplicity and to enable developer productivity, we’re firmly committed to developing all of Addepar’s services in the most recent version of Java ().

We use Facebook’s . We love that Buck includes support for incremental builds, (our unit test library of choice) with test result caching, , and support.

is our primary scripting language: we reach for it to quickly solve lightweight problems, often related to automation of our build and test infrastructure, ad-hoc data normalization, performance testing, and API development. There’s even an that wraps our publicly exposed API in an easy-to-use format.

We also use Python for configuration management. Specifically, we’re currently leveraging the ecosystem, which is written in Python and uses a great deal of the commonly used python libraries like . Salt acts as a distribution mechanism, propagating changes from the dedicated that stores our essential configuration settings onto our infrastructure.

We rely on for our critical secure configuration settings such as passwords, API keys, and SSL certificates.

Data Storage & Web Technology

Addepar receives and processes a wide variety of data in a multitude of formats every day. This complex and somewhat unwieldy dataset, when combined with our goal of persisting every piece of data Addepar has ever received, makes tracking and auditing complicated. Currently, to keep things as simple as possible, we persist daily custodian feed data in . We store the data in both the original form it was received and in the transformed form produced by our data processing pipeline. This enables us to easily go back and ‘reprocess’ a particular piece of data if needed.

Once data is processed and normalized by our pipeline, we persist it in a finalized form in . For our most frequently accessed financial data, we have a custom in-memory cache that is populated and synced to any data written to the database. Right above this cache sit our distributed web servers, which are responsible for serving any public facing HTTP requests from both our web app and our public REST APIs. We heavily lean on and for any use case requiring an HTTP interface, including our publicly facing endpoints. Finally, above the server layer, we utilize for load balancing, fault tolerance, and zero downtime deployments.

Messaging & Distributed Coordination

Since we abide by a service-oriented architecture in the backend, inter-process communication is critical. Addepar has invested fairly heavily in , particularly for , , and fault tolerance.

Kafka’s coordination power is built on — a distributed coordination server that’s also a natural supplement to Kafka. We use Zookeeper’s library to solve advanced problems like and service naming.


At its core, the Addepar web application is built using and we stick to vanilla JavaScript to be able to tap into the full potential of ES6.

We’re committed contributors to the Ember community. We’ve developed a number of open source projects, including , that we also use actively in our application. Because ours is an Ember application, our templating language is /HTMLBars and some of our dependencies are in /. We use as our testing framework, which lets us develop rapidly while ensuring a stable experience for our users. To deliver our powerful data visualizations, we use the . And we are currently using to bring the great Addepar design language to bear on the application.

We use to build the application, which allows us to streamline our development workflow and to tap into the ecosystem of . We also run the latest LTS and , giving us the benefits of modern javascript and package management.


This stack has served us quite well and it allows us to run our systems efficiently every day. However, we’re continuously thinking about potential improvements to prepare us for the challenges ahead. If you have any suggestions for our team, or if you’d like to learn more about engineering at Addepar, leave a comment or email us at !


Addepar Engineering + Design Blog

John Tylwalk

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Addepar Engineering + Design Blog