Getting Started

FIO Chain Action API

FIO Chain Action API allows a write transaction to be submitted to the FIO Chain. Unlike FIO Chain Getters, these transaction modify the blockchain and therefore must be signed by the user's FIO Private Key and serialized.


Not your typical REST API!

This API does not work like your typical REST API, but more like Layer 1 blockchain API. Make sure you read the Write Transactions Guide before proceeding. Your best bet is to use the FIO TypeScript SDK.

The API spec defines the parameters of each action to make it easy to read. However, these parameters have to be sent as part of a properly formatted, signed and serialized transaction and not as a json to the endpoint!

By that same token the documented response is just the relevant subset of the entire response you will receive.

There are two ways to submit the actions to the chain:

  • You can always use /push_transaction for any action you send
  • You can use the action specific endpoint as documented in this API spec.


No authentication is required. Remember, all transactions are signed with a private key.


There are many FIO Chain API servers ran by Block Producers and other entities. For latest server API urls, see

Here's a couple used on this site:

EndpointDescription Chain Testnet Chain Mainnet

Please note the v1 is static and does not represent the API version.