diff --git a/core/src/main/scala/caliban/interop/jsoniter/jsoniter.scala b/core/src/main/scala/caliban/interop/jsoniter/jsoniter.scala
index f154271e1..e2d5cd13b 100644
--- a/core/src/main/scala/caliban/interop/jsoniter/jsoniter.scala
+++ b/core/src/main/scala/caliban/interop/jsoniter/jsoniter.scala
@@ -123,7 +123,7 @@ private[caliban] object ValueJsoniter {
         StringValue(in.readString(null))
       case x if x == '-' || (x >= '0' && x <= '9') =>
         in.rollbackToken()
-        numberParser(in)
+        parseNumber(in)
       case 'n'                                     =>
         in.readNullOrError(NullValue, "unexpected JSON value")
       case 'f' | 't'                               =>
@@ -169,7 +169,7 @@ private[caliban] object ValueJsoniter {
         StringValue(in.readString(null))
       case x if x == '-' || (x >= '0' && x <= '9') =>
         in.rollbackToken()
-        numberParser(in)
+        parseNumber(in)
       case 'n'                                     =>
         in.readNullOrError(NullValue, "unexpected JSON value")
       case 'f' | 't'                               =>
@@ -203,32 +203,19 @@ private[caliban] object ValueJsoniter {
         in.decodeError(s"unexpected token $c")
     }
 
-  private val numberParser: JsonReader => Value = in => {
-    in.setMark()
-    var digits = 0
-    var b      = in.nextByte()
-    if (b == '-') b = in.nextByte()
-    try
-      while (b >= '0' && b <= '9') {
-        digits += 1
-        b = in.nextByte()
-      }
-    catch {
-      case _: JsonReaderException => // ignore the end of input error for now
+  private def parseNumber(in: JsonReader): Value =
+    in.readNumber(null) match {
+      case l: java.lang.Long        =>
+        val asLong = l.longValue()
+        val asInt  = asLong.toInt
+        // Check if the number can fit in an Int (most common case)
+        if (asInt.toLong == asLong) Value.IntValue.IntNumber(asInt)
+        else Value.IntValue.LongNumber(asLong)
+      case bd: java.math.BigDecimal =>
+        Value.FloatValue.BigDecimalNumber(bd)
+      case bi: java.math.BigInteger =>
+        Value.IntValue.BigIntNumber(bi)
     }
-    in.rollbackToMark()
-
-    if ((b | 0x20) != 'e' && b != '.') {
-      if (digits < 19) {
-        if (digits < 10) Value.IntValue.IntNumber(in.readInt())
-        else Value.IntValue.LongNumber(in.readLong())
-      } else {
-        val x = in.readBigInt(null)
-        if (x.bitLength < 64) Value.IntValue.LongNumber(x.longValue)
-        else Value.IntValue.BigIntNumber(x.bigInteger)
-      }
-    } else Value.FloatValue.BigDecimalNumber(in.readBigDecimal(null).bigDecimal)
-  }
 
   val inputValueCodec: JsonValueCodec[InputValue] = new JsonValueCodec[InputValue] {
     override def decodeValue(in: JsonReader, default: InputValue): InputValue =
diff --git a/core/src/test/scala/caliban/interop/jsoniter/GraphQLRequestJsoniterSpec.scala b/core/src/test/scala/caliban/interop/jsoniter/GraphQLRequestJsoniterSpec.scala
index 9a769ecc3..c498ba39b 100644
--- a/core/src/test/scala/caliban/interop/jsoniter/GraphQLRequestJsoniterSpec.scala
+++ b/core/src/test/scala/caliban/interop/jsoniter/GraphQLRequestJsoniterSpec.scala
@@ -11,7 +11,7 @@ object GraphQLRequestJsoniterSpec extends ZIOSpecDefault {
     suite("GraphQLRequestJsoniterSpec")(
       test("can be parsed from JSON by jsoniter") {
         val request =
-          """{"query": "{}", "operationName": "op", "variables": {"hello":"world","answer":42,"isAwesome":true, "name": null}}"""
+          """{"query": "{}", "operationName": "op", "variables": {"hello":"world","intValue":42,"longValue":99999999999,"bigIntValue":9223372036854775810,"decimalValue":1.1,"bigDecimalValue":4.4028235E38,"isAwesome":true, "name": null}}"""
         assert(readFromString[GraphQLRequest](request))(
           equalTo(
             GraphQLRequest(
@@ -19,10 +19,14 @@ object GraphQLRequestJsoniterSpec extends ZIOSpecDefault {
               operationName = Some("op"),
               variables = Some(
                 Map(
-                  "hello"     -> Value.StringValue("world"),
-                  "answer"    -> Value.IntValue(42),
-                  "isAwesome" -> Value.BooleanValue(true),
-                  "name"      -> Value.NullValue
+                  "hello"           -> Value.StringValue("world"),
+                  "intValue"        -> Value.IntValue.IntNumber(42),
+                  "longValue"       -> Value.IntValue.LongNumber(99999999999L),
+                  "bigIntValue"     -> Value.IntValue.BigIntNumber(BigInt("9223372036854775810")),
+                  "decimalValue"    -> Value.FloatValue(BigDecimal("1.1")),
+                  "bigDecimalValue" -> Value.FloatValue(BigDecimal("4.4028235E38")),
+                  "isAwesome"       -> Value.BooleanValue(true),
+                  "name"            -> Value.NullValue
                 )
               )
             )