MsgJoinPool

Joins an existing pool by providing liquidity. Users can join a pool by providing tokens proportional to the current pool composition. In return, they receive LP tokens representing their share of the pool.

Join Pool Properties

When joining a pool:

• Tokens must be provided in the correct proportions

• LP tokens are minted to the user

• Pool liquidity increases

• User becomes eligible for trading fees

Proto Definition

// ===================== MsgJoinPool
// This is really MsgJoinPoolNoSwap
message MsgJoinPool {
  option (amino.name) = "gamm/join-pool";
  option (cosmos.msg.v1.signer) = "sender";

  string sender = 1 [ (gogoproto.moretags) = "yaml:\"sender\"" ];
  uint64 pool_id = 2 [ (gogoproto.moretags) = "yaml:\"pool_id\"" ];
  string share_out_amount = 3 [

    (gogoproto.customtype) = "cosmossdk.io/math.Int",
    (gogoproto.moretags) = "yaml:\"pool_amount_out\"",
    (gogoproto.nullable) = false
  ];
  repeated cosmos.base.v1beta1.Coin token_in_maxs = 4 [
    (gogoproto.moretags) = "yaml:\"token_in_max_amounts\"",
    (gogoproto.nullable) = false
  ];
}

message MsgJoinPoolResponse {
  string share_out_amount = 1 [

    (gogoproto.customtype) = "cosmossdk.io/math.Int",
    (gogoproto.moretags) = "yaml:\"share_out_amount\"",
    (gogoproto.nullable) = false
  ];
  repeated cosmos.base.v1beta1.Coin token_in = 2 [
    (gogoproto.moretags) = "yaml:\"token_out\"",
    (gogoproto.nullable) = false
  ];
}

JSON Example

{
    "sender": "bb1abc123...",
    "pool_id": "1",
    "share_out_amount": "1000000",
    "token_in_maxs": [
        {
            "denom": "uatom",
            "amount": "100000"
        },
        {
            "denom": "uosmo",
            "amount": "500000"
        }
    ]
}

Token Proportions

The tokens provided must be in the same proportion as the current pool composition. If not, the transaction will fail or tokens will be returned.

Slippage Protection

The token_in_maxs field provides slippage protection by setting maximum amounts for each token that can be used in the join operation.

LP Token Minting

Upon successful join, LP tokens are minted to the user's address. These tokens represent ownership of the pool and can be used for:

• Earning trading fees

• Governance participation

• Staking in yield farming programs