Flow Client Library (FCL) enables applications to easily integrate with all FCL-compatible wallets and other services (e.g. (Coming Soon) profiles, private information, notifications). This offers developers a strong foundation to compose their apps with existing building blocks. It’s currently supported for browser applications, and will be extended to other platforms.

With FCL, you can:

Integrate all compatible wallets without any custom code or code injection
Authenticate users
Query the Flow Blockchain
Send transactions (e.g. initializing resources, sending assets, purchasing, etc.)
Sign transactions through wallet integration avoiding key management

With FCL, you will eventually be able to:

Personally sign data via FCL Compatible Wallets
Request Additional User info like Emails

Status

Last Updated: Mar 2nd 2021
Stable: Yes
Risk of Breaking Change: Low

The things that exists probably won't be changing much externally, we will be adding new functionality in the near future.

Install

npm install --save @onflow/fcl

Getting Started

For a detailed guide explaining how to use @onflow/fcl to interact with Flow please see the Flow App Quick Start

Having trouble with something? Reach out to us on Discord, we are more than happy to help.

FAQs

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Package last updated on 25 Mar 2026

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