Koinos Namespace - Chains

Author Roamin
Status Draft
Type Standard
Created 2023-04-10
Requires CAIP-2


For context, see the CAIP-2 specification.


In CAIP-2, a general blockchain identification scheme is defined. This is the implementation of CAIP-2 for networks that are based on the Koinos Blockchain Framework.

Koinos Namespace

The namespace “koinos” refers to the wider Koinos Blockchain Framework ecosystem.


Koinos consists of multiple networks: a production network (Mainnet) and a testing network (TestNet). Each network has a unique chain id that can be used to identify it.

An identifier for a Koinos chain consists of the namespace prefix “koinos:” followed by a truncated form of the chain id.


Due to length and character limitations of CAIP-2 reference identifiers (references must adhere to [-_a-zA-Z0-9]{1,32}), the chain id of a Koinos chain cannot be used directly as a reference.

Instead, only the first 32 characters of the URL-safe base64-encoding chain id will be used.

Resolution Method

To resolve the chain id for a Koinos chain, a GET request can be made to a Koinos node using the JSON-RPC method chain.get_chain_id. This will return a JSON object with the key chain_id, whose value is the base64-url chain id of the current chain.

For example:

// Request
curl -d '{"jsonrpc":"2.0", "method":"chain.get_chain_id", "params":{}, "id":0}' https://api.koinos.io

// Response (formatted)
  "jsonrpc": "2.0",
  "result": {
    "chain_id": "EiBZK_GGVP0H_fXVAM3j6EAuz3-B-l3ejxRSewi7qIBfSA=="
  "id": 0

Note that the chain_id value returned must be substringed to the first 32 characters.

For example, this JavaScript code transforms the above response into a CAIP-2 identifier:

// For the Koinos mainnet
const chainId = "EiBZK_GGVP0H_fXVAM3j6EAuz3-B-l3ejxRSewi7qIBfSA==";
const prefix = chainId.substring(0, 32);
const identifier = "koinos:" + prefix;

console.log(identifier); // prints "koinos:EiBZK_GGVP0H_fXVAM3j6EAuz3-B-l3e"

Backwards Compatibility

Not applicable.

Test Cases

# Koinos Mainnet (chain id= EiBZK_GGVP0H_fXVAM3j6EAuz3-B-l3ejxRSewi7qIBfSA== )

# Koinos Harbinger (Testnet; chain id= EiAAKqFi-puoXnuJTdn7qBGGJa8yd-dcS2P0ciODe4wupQ== )



Copyright and related rights waived via CC0.


Please cite this document as:

Roamin, "namespaces/koinos-caip2: Koinos Namespace - Chains [DRAFT]," Chain Agnostic Namespaces, koinos-caip2, April 2023 / . [Online serial]. Available: https://github.com/ChainAgnostic/namespaces/koinos-caip2.md