diff --git a/exchanges/okx/okx_test.go b/exchanges/okx/okx_test.go
index 15325657..bcbca667 100644
--- a/exchanges/okx/okx_test.go
+++ b/exchanges/okx/okx_test.go
@@ -3125,3 +3125,100 @@ func TestGetIntervalEnum(t *testing.T) {
 		})
 	}
 }
+
+const instrumentJSON = `{"alias":"","baseCcy":"","category":"1","ctMult":"1","ctType":"linear","ctVal":"0.0001","ctValCcy":"BTC","expTime":"","instFamily":"BTC-USDC","instId":"BTC-USDC-SWAP","instType":"SWAP","lever":"125","listTime":"1666076190000","lotSz":"1","maxIcebergSz":"100000000.0000000000000000","maxLmtSz":"100000000","maxMktSz":"85000","maxStopSz":"85000","maxTriggerSz":"100000000.0000000000000000","maxTwapSz":"","minSz":"1","optType":"","quoteCcy":"","settleCcy":"USDC","state":"live","stk":"","tickSz":"0.1","uly":"BTC-USDC"}`
+
+func TestInstrument(t *testing.T) {
+	t.Parallel()
+
+	var i Instrument
+	err := json.Unmarshal([]byte(instrumentJSON), &i)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if i.Alias != "" {
+		t.Error("expected empty alias")
+	}
+	if i.BaseCurrency != "" {
+		t.Error("expected empty base currency")
+	}
+	if i.Category != "1" {
+		t.Error("expected 1 category")
+	}
+	if i.ContractMultiplier != "1" {
+		t.Error("expected 1 contract multiplier")
+	}
+	if i.ContractType != "linear" {
+		t.Error("expected linear contract type")
+	}
+	if i.ContractValue != "0.0001" {
+		t.Error("expected 0.0001 contract value")
+	}
+	if i.ContractValueCurrency != currency.BTC.String() {
+		t.Error("expected BTC contract value currency")
+	}
+	if !i.ExpTime.IsZero() {
+		t.Error("expected empty expiry time")
+	}
+	if i.InstrumentFamily != "BTC-USDC" {
+		t.Error("expected BTC-USDC instrument family")
+	}
+	if i.InstrumentID != "BTC-USDC-SWAP" {
+		t.Error("expected BTC-USDC-SWAP instrument ID")
+	}
+	if i.InstrumentType != asset.PerpetualSwap {
+		t.Error("expected SWAP instrument type")
+	}
+	if i.MaxLeverage != 125 {
+		t.Error("expected 125 leverage")
+	}
+	if i.ListTime.UnixMilli() != 1666076190000 {
+		t.Error("expected 1666076190000 listing time")
+	}
+	if i.LotSize != 1 {
+		t.Error("expected 1 lot size")
+	}
+	if i.MaxSpotIcebergSize != 100000000.0000000000000000 {
+		t.Error("expected 100000000.0000000000000000 max iceberg order size")
+	}
+	if i.MaxQuantityOfSpotLimitOrder != 100000000 {
+		t.Error("expected 100000000 max limit order size")
+	}
+	if i.MaxQuantityOfMarketLimitOrder != 85000 {
+		t.Error("expected 85000 max market order size")
+	}
+	if i.MaxStopSize != 85000 {
+		t.Error("expected 85000 max stop order size")
+	}
+	if i.MaxTriggerSize != 100000000.0000000000000000 {
+		t.Error("expected 100000000.0000000000000000 max trigger order size")
+	}
+	if i.MaxQuantityOfSpotTwapLimitOrder != 0 {
+		t.Error("expected empty max TWAP size")
+	}
+	if i.MinimumOrderSize != 1 {
+		t.Error("expected 1 min size")
+	}
+	if i.OptionType != "" {
+		t.Error("expected empty option type")
+	}
+	if i.QuoteCurrency != "" {
+		t.Error("expected empty quote currency")
+	}
+	if i.SettlementCurrency != currency.USDC.String() {
+		t.Error("expected USDC settlement currency")
+	}
+	if i.State != "live" {
+		t.Error("expected live state")
+	}
+	if i.StrikePrice != "" {
+		t.Error("expected empty strike price")
+	}
+	if i.TickSize != 0.1 {
+		t.Error("expected 0.1 tick size")
+	}
+	if i.Underlying != "BTC-USDC" {
+		t.Error("expected BTC-USDC underlying")
+	}
+}
diff --git a/exchanges/okx/okx_type_convert.go b/exchanges/okx/okx_type_convert.go
index 132339c6..acd0d746 100644
--- a/exchanges/okx/okx_type_convert.go
+++ b/exchanges/okx/okx_type_convert.go
@@ -2,7 +2,6 @@ package okx
 
 import (
 	"encoding/json"
-	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -65,40 +64,84 @@ func (a *okxUnixMilliTime) Time() time.Time {
 	return time.UnixMilli(int64(*a))
 }
 
-// numbersOnlyRegexp for checking the value is numerics only
-var numbersOnlyRegexp = regexp.MustCompile(`^\d*$`)
+type okxTime struct {
+	time.Time
+}
+
+// UnmarshalJSON deserializes byte data to okxTime instance.
+func (t *okxTime) UnmarshalJSON(data []byte) error {
+	var num string
+	err := json.Unmarshal(data, &num)
+	if err != nil {
+		return err
+	}
+	if num == "" {
+		return nil
+	}
+	value, err := strconv.ParseInt(num, 10, 64)
+	if err != nil {
+		return err
+	}
+	t.Time = time.UnixMilli(value)
+	return nil
+}
+
+type okxAssetType struct {
+	asset.Item
+}
+
+// UnmarshalJSON deserializes JSON, and timestamp information.
+func (a *okxAssetType) UnmarshalJSON(data []byte) error {
+	var t string
+	err := json.Unmarshal(data, &t)
+	if err != nil {
+		return err
+	}
+
+	a.Item, err = GetAssetTypeFromInstrumentType(strings.ToUpper(t))
+
+	return err
+}
 
 // UnmarshalJSON deserializes JSON, and timestamp information.
 func (a *Instrument) UnmarshalJSON(data []byte) error {
 	type Alias Instrument
 	chil := &struct {
 		*Alias
-		ListTime       string `json:"listTime"`
-		ExpTime        string `json:"expTime"`
-		InstrumentType string `json:"instType"`
+		ListTime                        okxTime           `json:"listTime"`
+		ExpTime                         okxTime           `json:"expTime"`
+		InstrumentType                  okxAssetType      `json:"instType"`
+		MaxLeverage                     okxNumericalValue `json:"lever"`
+		TickSize                        okxNumericalValue `json:"tickSz"`
+		LotSize                         okxNumericalValue `json:"lotSz"`
+		MinimumOrderSize                okxNumericalValue `json:"minSz"`
+		MaxQuantityOfSpotLimitOrder     okxNumericalValue `json:"maxLmtSz"`
+		MaxQuantityOfMarketLimitOrder   okxNumericalValue `json:"maxMktSz"`
+		MaxQuantityOfSpotTwapLimitOrder okxNumericalValue `json:"maxTwapSz"`
+		MaxSpotIcebergSize              okxNumericalValue `json:"maxIcebergSz"`
+		MaxTriggerSize                  okxNumericalValue `json:"maxTriggerSz"`
+		MaxStopSize                     okxNumericalValue `json:"maxStopSz"`
 	}{
 		Alias: (*Alias)(a),
 	}
-	err := json.Unmarshal(data, chil)
-	if err != nil {
-		return err
-	}
-	if numbersOnlyRegexp.MatchString(chil.ListTime) {
-		var val int
-		if val, err = strconv.Atoi(chil.ListTime); err == nil {
-			a.ListTime = time.UnixMilli(int64(val))
-		}
-	}
-	if numbersOnlyRegexp.MatchString(chil.ExpTime) {
-		var val int
-		if val, err = strconv.Atoi(chil.ExpTime); err == nil {
-			a.ExpTime = time.UnixMilli(int64(val))
-		}
-	}
-	chil.InstrumentType = strings.ToUpper(chil.InstrumentType)
-	if a.InstrumentType, err = GetAssetTypeFromInstrumentType(chil.InstrumentType); err != nil {
+	if err := json.Unmarshal(data, chil); err != nil {
 		return err
 	}
+
+	a.ListTime = chil.ListTime.Time
+	a.ExpTime = chil.ExpTime.Time
+	a.InstrumentType = chil.InstrumentType.Item
+	a.MaxLeverage = chil.MaxLeverage.Float64()
+	a.TickSize = chil.TickSize.Float64()
+	a.LotSize = chil.LotSize.Float64()
+	a.MinimumOrderSize = chil.MinimumOrderSize.Float64()
+	a.MaxQuantityOfSpotLimitOrder = chil.MaxQuantityOfSpotLimitOrder.Float64()
+	a.MaxQuantityOfMarketLimitOrder = chil.MaxQuantityOfMarketLimitOrder.Float64()
+	a.MaxQuantityOfSpotTwapLimitOrder = chil.MaxQuantityOfSpotTwapLimitOrder.Float64()
+	a.MaxSpotIcebergSize = chil.MaxSpotIcebergSize.Float64()
+	a.MaxTriggerSize = chil.MaxTriggerSize.Float64()
+	a.MaxStopSize = chil.MaxStopSize.Float64()
+
 	return nil
 }
 
diff --git a/exchanges/okx/okx_types.go b/exchanges/okx/okx_types.go
index dc08b75f..2a35605f 100644
--- a/exchanges/okx/okx_types.go
+++ b/exchanges/okx/okx_types.go
@@ -274,33 +274,34 @@ type InstrumentsFetchParams struct {
 
 // Instrument  representing an instrument with open contract.
 type Instrument struct {
-	InstrumentType                  asset.Item        `json:"instType"`
-	InstrumentID                    string            `json:"instId"`
-	Underlying                      string            `json:"uly"`
-	Category                        string            `json:"category"`
-	BaseCurrency                    string            `json:"baseCcy"`
-	QuoteCurrency                   string            `json:"quoteCcy"`
-	SettlementCurrency              string            `json:"settleCcy"`
-	ContractValue                   string            `json:"ctVal"`
-	ContractMultiplier              string            `json:"ctMult"`
-	ContractValueCurrency           string            `json:"ctValCcy"`
-	OptionType                      string            `json:"optType"`
-	StrikePrice                     string            `json:"stk"`
-	ListTime                        time.Time         `json:"listTime"`
-	ExpTime                         time.Time         `json:"expTime"`
-	MaxLeverage                     okxNumericalValue `json:"lever"`
-	TickSize                        okxNumericalValue `json:"tickSz"`
-	LotSize                         okxNumericalValue `json:"lotSz"`
-	MinimumOrderSize                okxNumericalValue `json:"minSz"`
-	ContractType                    string            `json:"ctType"`
-	Alias                           string            `json:"alias"`
-	State                           string            `json:"state"`
-	MaxQuantityOfSpotLimitOrder     float64           `json:"maxLmtSz,string"`
-	MaxQuantityOfMarketLimitOrder   float64           `json:"maxMktSz,string"`
-	MaxQuantityOfSpotTwapLimitOrder float64           `json:"maxTwapSz,string"`
-	MaxSpotIcebergSize              float64           `json:"maxIcebergSz,string"`
-	MaxTriggerSize                  float64           `json:"maxTriggerSz,string"`
-	MaxStopSize                     float64           `json:"maxStopSz,string"`
+	InstrumentType                  asset.Item `json:"instType"`
+	InstrumentID                    string     `json:"instId"`
+	InstrumentFamily                string     `json:"instFamily"`
+	Underlying                      string     `json:"uly"`
+	Category                        string     `json:"category"`
+	BaseCurrency                    string     `json:"baseCcy"`
+	QuoteCurrency                   string     `json:"quoteCcy"`
+	SettlementCurrency              string     `json:"settleCcy"`
+	ContractValue                   string     `json:"ctVal"`
+	ContractMultiplier              string     `json:"ctMult"`
+	ContractValueCurrency           string     `json:"ctValCcy"`
+	OptionType                      string     `json:"optType"`
+	StrikePrice                     string     `json:"stk"`
+	ListTime                        time.Time  `json:"listTime"`
+	ExpTime                         time.Time  `json:"expTime"`
+	MaxLeverage                     float64    `json:"lever"`
+	TickSize                        float64    `json:"tickSz"`
+	LotSize                         float64    `json:"lotSz"`
+	MinimumOrderSize                float64    `json:"minSz"`
+	ContractType                    string     `json:"ctType"`
+	Alias                           string     `json:"alias"`
+	State                           string     `json:"state"`
+	MaxQuantityOfSpotLimitOrder     float64    `json:"maxLmtSz"`
+	MaxQuantityOfMarketLimitOrder   float64    `json:"maxMktSz"`
+	MaxQuantityOfSpotTwapLimitOrder float64    `json:"maxTwapSz"`
+	MaxSpotIcebergSize              float64    `json:"maxIcebergSz"`
+	MaxTriggerSize                  float64    `json:"maxTriggerSz"`
+	MaxStopSize                     float64    `json:"maxStopSz"`
 }
 
 // DeliveryHistoryDetail holds instrument id and delivery price information detail
diff --git a/exchanges/okx/okx_wrapper.go b/exchanges/okx/okx_wrapper.go
index bdcb411b..617bd89d 100644
--- a/exchanges/okx/okx_wrapper.go
+++ b/exchanges/okx/okx_wrapper.go
@@ -341,8 +341,8 @@ func (ok *Okx) UpdateOrderExecutionLimits(ctx context.Context, a asset.Item) err
 		limits[x] = order.MinMaxLevel{
 			Pair:                   pair,
 			Asset:                  a,
-			PriceStepIncrementSize: insts[x].TickSize.Float64(),
-			MinAmount:              insts[x].MinimumOrderSize.Float64(),
+			PriceStepIncrementSize: insts[x].TickSize,
+			MinAmount:              insts[x].MinimumOrderSize,
 		}
 	}