@x402/core becomes the reference TypeScript client/server SDK

Package cadence is a developer-activity signal for the protocol’s real adoption, not GitHub stars.

The @x402/core, @x402/evm, @x402/fetch and @x402/express packages are the maintained TypeScript implementation path used by sellers and buyers. Version lines in the 2.x series indicate HTTP-header transport rather than early prototypes.

Why it matters

SDK version skew is a buyer-support issue. Foundry pins specific 2.x versions; market intelligence should track breaking changes.

Source: coinbase/x402

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