Error 400100: Price increment invalid.

[BaseMax]

POST /api/v1/orders

Document: https://docs.kucoin.com/#place-a-new-order

Input:

{"clientOid":"62935e628a049","price":"1.08171","size":"15","symbol":"GMT-USDT","type":"limit","side":"buy","remark":"ORDER#1653825122"}

Response:

{"code":"400100","msg":"Price increment invalid."}

Can you help what is this error and how can fix it?

[codewc]

POST /api/v1/orders

Document: https://docs.kucoin.com/#place-a-new-order

Input:

{"clientOid":"62935e628a049","price":"1.08171","size":"15","symbol":"GMT-USDT","type":"limit","side":"buy","remark":"ORDER#1653825122"}

Response:

{"code":"400100","msg":"Price increment invalid."}

Can you help what is this error and how can fix it?

The priceIncrement field specifies the min order price as well as the price increment.This also applies to quote currency. The order price must be a positive integer multiple of this priceIncrement (i.e. if the increment is 0.01, the 0.001 and 0.021 order prices would be rejected). refer to: https://docs.kucoin.com/#get-symbols-list

The data is what I queried from the GET /api/v1/symbols interface

       {
            "symbol": "GMT-USDT",
            "name": "GMT-USDT",
            "baseCurrency": "GMT",
            "quoteCurrency": "USDT",
            "feeCurrency": "USDT",
            "market": "USDS",
            "baseMinSize": "1",
            "quoteMinSize": "0.1",
            "baseMaxSize": "10000000000",
            "quoteMaxSize": "99999999",
            "baseIncrement": "0.0001",
            "quoteIncrement": "0.0001",
            "priceIncrement": "0.0001",
            "priceLimitRate": "0.1",
            "minFunds": "0.1",
            "isMarginEnabled": true,
            "enableTrading": true
        },

the "priceIncrement" is "0.0001", so your correct price should be 1.0817 not 1.08171.

[BaseMax]

Thank you for your help and description.

[BaseMax]

Solution code to fix the price for this coin:

<?php
function fixPrice($price, $priceIncrement) {
    return number_format($price, 4);
}
// "priceIncrement": "0.0001",
$price = 1.08171;
print fixPrice($price, "0.0001");

[BaseMax]

A bit more complicated solution, Anyway this is not a perfect and smart solution.

<?php
// GMT:    0.0001
// KCS:    0.001
function fixPrice(float $price, string $priceIncrement) : string
{
    $price = (string) $price;
    if ($priceIncrement === "0.000000001") {
        return number_format($price, 9);
    }
    else if ($priceIncrement === "0.00000001") {
        return number_format($price, 8);
    }
    else if ($priceIncrement === "0.0000001") {
        return number_format($price, 7);
    }
    else if ($priceIncrement === "0.000001") {
        return number_format($price, 6);
    }
    else if ($priceIncrement === "0.00001") {
        return number_format($price, 5);
    }
    else if ($priceIncrement === "0.0001") {
        return number_format($price, 4);
    }
    else if ($priceIncrement === "0.001") {
        return number_format($price, 3);
    }
    else if ($priceIncrement === "0.01") {
        return number_format($price, 2);
    }
    else if ($priceIncrement === "0.1") {
        return number_format($price, 1);
    }
    return $price;
}

Test:

$price = 1.08171;
print fixPrice($price, "0.0001");

The best way is to call GET /api/v1/symbols and automatically fix the price format by priceIncrement.

[hhxsv5]

• Call functions of BC Math to do the mathematics.
• Call log10() to calculate precision.

  function fixPrice(string $price, string $priceIncrement) 
  {
  $precision = max(log10(1 / $priceIncrement), 0);
  return bcadd($price, '0', $precision);
  }

[BaseMax]

Your solution is too smart. @hhxsv5 👍 Thanks, Biao.