Life After IEX Cloud: Best Replacement Data APIs

Life After IEX Cloud: Best Replacement Data APIs

IEX Cloud has shut down. This is a migration guide for displaced users, organized by the job the data has to do.

What Happened to IEX Cloud

IEX Cloud, the data platform spun out of the IEX exchange, wound down its service and retired its APIs, leaving a large base of developers and small quant shops needing a replacement. It had been a popular middle-ground option: cleaner and more developer-friendly than scraping, cheaper and more accessible than enterprise feeds. Its closure removed a default that many projects had quietly depended on.

Because IEX Cloud served several distinct use cases at once, there is no single drop-in replacement. The right migration depends on which part of the platform you actually used. The sensible approach is to map your usage to the job it did, then pick the best replacement for that job.

Replacements by Use Case

For real-time and historical prices. Polygon.io (Massive) is the most direct successor for most former IEX Cloud users, with broad US price coverage, flat-rate pricing, and both REST and WebSocket access. Our guide to Polygon (Massive) alternatives is useful if you want to compare it against its own peers before committing.

For fundamentals and ratios. FinancialModelingPrep covers the financial-statement and screening use cases at a flat rate. For news and quotes on a budget, Finnhub and Tiingo both offer accessible tiers. For tick-level depth, Databento provides institutional-grade data through a modern API.

For reference and corporate-action data. This is the category IEX Cloud handled least well, and the one most often forgotten in a migration. Splits, dividends, ticker changes, and listing status all need a source, and getting them wrong silently corrupts a backtest. Some price APIs bundle basic corporate actions, but financing events and point-in-time universe membership require a dedicated dataset rather than a price feed.

If cost is the deciding factor, our guide to the best free stock market APIs is candid about the free tiers, and our roundup of the best market data APIs for algorithmic trading sorts the full field by use case so you can match the replacement to your workflow.

Comparison Table

The migration is also a chance to avoid repeating a mistake. Many IEX Cloud users had quietly built single-vendor dependence, with prices, fundamentals, and quotes all flowing from one convenient source. The shutdown is a reminder that a data vendor is infrastructure, and infrastructure can disappear. A stack assembled from two or three specialist providers, each replaceable on its own, is more resilient than one platform doing everything, even if it takes slightly more wiring up front.

There is a practical sequencing point as well. Migrate your highest-frequency dependency first, usually the live price feed, since that is what breaks visibly when an API goes dark. Backfill historical and fundamental data second, where you have more time to validate quality. Treating the move as staged rather than all-at-once reduces the risk of swapping one fragile single source for another.

Rebuild the Research Layer While You Migrate

A forced migration is an opportunity to fix a weakness IEX Cloud shared with its replacements. None of these providers ship the structured research datasets that a systematic backtest depends on. They give you prices and fundamentals, not point-in-time universe membership or dated corporate-event history.

As you stand up a new price feed, add the research layer you may have been missing all along. Alphanume's historical market cap dataset provides point-in-time size for universe construction, and the dilution events feed turns SEC filings into machine-readable events for event-driven work. Getting started is a matter of an API key and a few requests, and the result is a stack that is both replacement and upgrade.

How to Choose

Do not look for one product to replace IEX Cloud. Identify the two or three jobs you used it for, pick the strongest replacement for each, and treat the migration as a chance to add the point-in-time research datasets that no general-purpose price API provided. The platform that displaced you was a convenience layer, and the stack you build to replace it can be more capable than what you lost.