> For the complete documentation index, see [llms.txt](https://docs.quipuswap.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.quipuswap.com/smart-contracts/dex-2.0/dexcore-contract/entrypoints-overview/dex-entrypoints/invest_liquidity.md).

# invest\_liquidity

An entrypoint for liquidity investment in the specific liquidity pool (pair). Also it [votes](/smart-contracts/dex-2.0/bucket-contract/entrypoints-overview/vote.md) for the users' bakers in case of liquidity investment to TOK/TEZ pools.

### Call parameters

```pascaligo
type token_id_t         is nat

type invest_liquidity_t is [@layout:comb] record [
  pair_id                 : token_id_t;
  token_a_in              : nat;
  token_b_in              : nat;
  shares                  : nat;
  shares_receiver         : address;
  candidate               : key_hash;
  deadline                : timestamp;
]
```

<table><thead><tr><th width="191">Field</th><th width="150">Type</th><th>Description</th></tr></thead><tbody><tr><td>pair_id</td><td>token_id_t (nat)</td><td>Identifier of the liquidity pool (pair)</td></tr><tr><td>token_a_in</td><td>nat</td><td>Max amount of token A allowed to be spent</td></tr><tr><td>token_b_in</td><td>nat</td><td>Max amount of token B allowed to be spent</td></tr><tr><td>shares</td><td>nat</td><td>Amount of LP tokens to be acquired</td></tr><tr><td>shares_receiver</td><td>address</td><td>Receiver of LP tokens</td></tr><tr><td>candidate</td><td>key_hash</td><td>Baker for voting (is used only in time of investment to TOK/TEZ exchanges)</td></tr><tr><td>deadline</td><td>timestamp</td><td>The time until which the transaction remains valid and will not be rejected</td></tr></tbody></table>

### Usage

{% hint style="danger" %}
Note: you need to pass positive TEZ/mutez amount to the ***send()*** method in case of FA1.2/TEZ or FA2/TEZ liquidity investment (see example below).

Also don't forget to add the [DexCore](/smart-contracts/dex-2.0/dexcore-contract.md) contract as the operator for your FA2 tokens or make an approve for spending of FA1.2 tokens in time of liquidity investment.
{% endhint %}

{% tabs %}
{% tab title="🌮 Taquito" %}

```javascript
const dexCoreAddress = "KT1...";
const parmas = {
    pair_id: 0,
    token_a_in: 100,
    token_b_in: 100,
    shares: 100,
    shares_receiver: "tz1.../KT1...",
    candidate: "tz1...",
    deadline: String(Date.parse((await tezos.rpc.getBlockHeader()).timestamp) / 1000 + 100),
};
const dexCore = await tezos.contract.at(dexCoreAddress);
const operation = await dexCore.methodsObject.invest_liquidity(parmas).send({ amount: parmas.token_b_in, mutez: true });

await operation.confirmation();
```

{% endtab %}
{% endtabs %}

{% hint style="info" %}
Pass `candidate: "tz1ZZZZZZZZZZZZZZZZZZZZZZZZZZZZNkiRg"`in case of TOK/TOK exchange
{% endhint %}

### Errors

* `108` - pair (pool) with the specified `token_id` not listed.
* `109` - pair doesn't have a liquidity.
* `110` - zero amount of LP tokens (shares) expected.
* `111` - low token A amount in.
* `112` - low token B amount in.
* `136` - reentrancy.
* `141` - wrong amount of TEZ tokens were attached to transaction.
* `144` - action outdated (the time until which the transaction remained valid was passed).
* `412` - non payable entrypoint (can't accept TEZ tokens during call of an entrypoint). Only in case of investment to TOK/TOK liquidity pools (pairs).