Quandl (Nasdaq Data Link)

Quandl, now operating as Nasdaq Data Link, is a leading financial and alternative data marketplace originally founded in 2012 and acquired by Nasdaq in December 2018. Rebranded in September 2021, the platform serves over 650,000 financial professionals worldwide, offering access to more than 250 curated datasets from Nasdaq and third-party data providers through a single, standardized API.

The platform operates as a data marketplace where users subscribe to individual datasets covering equities, options, futures, forex, economic indicators, and alternative data. Free datasets — including Federal Reserve data, real estate metrics, and consumer sentiment indices — are available at no cost with a free account. Premium datasets are priced à la carte per subscription, with free sample data available before committing to a purchase, making it easy to evaluate data quality before spending.

Nasdaq Data Link is built API-first, offering a RESTful interface that returns data in CSV, JSON, or XML formats. Official SDKs are available for Python, R, Ruby, and Excel, making integration straightforward for quantitative analysts and developers. Premium subscribers see rate limits increase from 50,000 API calls per day on the free tier to 720,000 per day, along with full database bulk download capabilities. The platform also integrates natively with QuantConnect for algorithmic trading workflows.

What distinguishes Nasdaq Data Link is the combination of Nasdaq's institutional-grade data infrastructure with a curated marketplace of third-party alternative datasets — all accessible through one API. This makes it a primary resource for quants, data scientists, and institutional investors seeking both traditional financial data and differentiated alternative datasets for systematic alpha generation.