# Exact input and exact output

> Quote by the amount you pay or by the amount you receive.

This page is part of the DEX Aggregator docs. The aggregator is at `https://router.intear.tech`, with live quotes at `wss://router.intear.tech/route/subscribe`, on NEAR mainnet only. https://docs.intear.tech/dex-aggregator/llms-full.txt has all of its pages in one file, and https://docs.intear.tech/llms.txt lists every page of the Intear docs.

Pass exactly one of `amount_in` or `amount_out`. Both are raw integers in the token's smallest unit (use the token's `decimals` from `ft_metadata`).

## Exact input: `amount_in`

"I pay exactly this much, how much do I get?" This is the most common mode, and every DEX supports it.

```
amount_in=1000000000000000000000000
```

Quotes come back with output amounts:

```json
"estimated_amount": { "amount_out": "4880007" },
"worst_case_amount": { "amount_out": "4831206" }
```

`worst_case_amount` is the minimum output the transactions accept. If the pools move so that the output would be lower, the swap fails and the input is refunded.

## Exact output: `amount_out`

"I want to receive exactly this much, how much do I pay?"

```
amount_out=1000000
```

Quotes come back with input amounts:

```json
"estimated_amount": { "amount_in": "205495745391126196067546" },
"worst_case_amount": { "amount_in": "210222147535122098577099" }
```

`worst_case_amount` is the most the trader can pay. The transactions send up to this much and return whatever isn't used, so the trader needs to hold the worst-case amount, not just the estimate.

Not every DEX supports exact output:

| DEX | Exact output |
| --- | --- |
| Rhea | ❌ No |
| Rhea DCL | ✅ Yes |
| IntearDex | ✅ Yes |
| Wrap | ✅ Yes |

DEXs that don't support it just don't return a quote, so you may get fewer quotes than with `amount_in`.

## Fee discounts

Traders holding or staking TEAR (`token.intear.near`) get a discount on Plach's pool and protocol fees, signed into the route by the aggregator:

| TEAR held or staked | Fee discount |
| --- | --- |
| 10 | 10% |
| 1,000 | 25% |
| 100,000 | 75% |

The discount is signed for the trader, so pass `trader_account_id` to get it. The aggregator adds up the trader's TEAR in the wallet and staked in `stakeyourtears.intear.near`, and reads it again when it's over a minute old. The first quote for a trader comes without the discount while it's read, so request a new quote before executing. Referral fees aren't discounted. The signed discount expires after about 10 minutes (1000 blocks), and the swap fails after that, so refresh old quotes before executing them.

The quote's `discount` says how much it saves, in the same direction as `estimated_amount`:

```json
"estimated_amount": { "amount_out": "4880007" },
"worst_case_amount": { "amount_out": "4831206" },
"discount": { "amount_out": "1952" }
```

With `amount_in`, `discount` is the extra output the trader gets, so you can show it as a bonus. With `amount_out`, it's `{"amount_in": "..."}`, how much less the trader pays.

`estimated_amount` and `worst_case_amount` already include the discount, so don't add it again. It can be `0` when the discount doesn't change the result, for example on very small amounts. Quotes without a fee discount, because they're not IntearDex or Plach quotes, have no `trader_account_id`, are the first quote for the trader, or the trader holds and stakes less than 10 TEAR together, have no `discount` field.