Allium, a blockchain data provider that counts Visa and Coinbase among the users of its data, has confirmed that an unauthorized party gained access to some of its systems. The company detected the incident on October 25.

Chief Executive Officer and co-founder Ethan Chan said Allium restricted access after discovering the intrusion. The company notified affected customers directly and hired an independent cybersecurity firm to investigate.

Allium has not named the attacker or explained how the access occurred. It has also not said whether customer or end-user data was exposed.

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Services and API Keys

Allium's incident history shows its Explorer became unavailable on October 25, and the company took its application offline the following day as a precaution. By October 28, the main application, the Explorer and related APIs were working again.

Existing API keys, the credentials customers use to pull Allium's data into their own systems, were revoked, and customers were told to create new ones in the app or obtain them from their Allium contacts. The company also recommended password resets and multifactor authentication.

Access to previously uploaded datasets, as well as the ability to upload new data, remained disabled. Queries that depend on those tables could not run. Allium Assistant and its Model Context Protocol (MCP) service, an open standard that lets AI applications connect to external data sources, were likewise still unavailable in the October 28 notice.

Data Feeds Affected

The incident coincided with disruptions to Allium's data delivery services, which supply blockchain data to companies using Snowflake, Databricks and Google BigQuery, the enterprise platforms businesses use to store and query large datasets.

An October 26 update said datashare tables were no longer receiving fresh data, meaning customers could see stale results or errors. Delivery has since restarted on all three platforms, although Allium said it was still checking for missing records and filling gaps from the affected period.

Ethereum, Bitcoin, Solana and Base datasets on Snowflake and Databricks were being checked for freshness and completeness. Backfilling continued for other chains and for all chains on BigQuery, while work on Hyperliquid was still in progress.

Customers and Funding

Allium was founded in 2021 and serves institutional customers. It lists Visa and Coinbase as users of its data, and Visa's onchain analytics dashboard states that it is powered by Allium — an example of how institutional crypto tooling often rests on specialized data vendors.

The disclosure does not say that Visa, Stripe or Coinbase had their own systems accessed. Allium did not name the customers it notified.

In June, Allium announced a $40 million Series B funding round led by Amplify Partners, with Kleiner Perkins and Theory Ventures also taking part. The company said at the time that its technology supported data operations across more than 150 blockchains.

Chan said Allium is strengthening its authentication and monitoring. "We're sorry for the disruption this has caused our customers," he wrote.

Allium plans to share a summary of its findings and response measures after the investigation ends. It has not said when that will happen.