diff --git a/tribune-core/src/main/kotlin/com/sksamuel/tribune/core/strings/strings.kt b/tribune-core/src/main/kotlin/com/sksamuel/tribune/core/strings/strings.kt
index f026212..ee2f7cf 100644
--- a/tribune-core/src/main/kotlin/com/sksamuel/tribune/core/strings/strings.kt
+++ b/tribune-core/src/main/kotlin/com/sksamuel/tribune/core/strings/strings.kt
@@ -1,5 +1,6 @@
 package com.sksamuel.tribune.core.strings
 
+import arrow.core.Either
 import arrow.core.leftNel
 import arrow.core.right
 import com.sksamuel.tribune.core.Parser
@@ -41,16 +42,23 @@ fun <I, E> Parser<I, String?, E>.notNullOrBlank(ifError: () -> E): Parser<I, Str
 }
 
 /**
- * Wraps an existing String -> String [Parser] to reject blank strings,
+ * Wraps an existing I -> String? [Parser] to reject blank strings,
  * with the error message generated by the given function [ifBlank].
  *
+ * Note: This parser accepts null strings as valid. If you wish to reject null inputs as well,
+ * then use nullOrNotBlank.
+ *
  * @param ifBlank the error generating function
  *
  * @return invalid if the input string contains only whitespace, otherwise valid
  */
-fun <I, E> Parser<I, String, E>.notBlank(ifBlank: () -> E): Parser<I, String, E> {
+fun <I, E> Parser<I, String?, E>.notBlank(ifBlank: () -> E): Parser<I, String?, E> {
    return flatMap {
-      if (it.isBlank()) ifBlank().leftNel() else it.right()
+      when {
+         it == null -> Either.Right(null)
+         it.isBlank() -> ifBlank().leftNel()
+         else -> it.right()
+      }
    }
 }
 
diff --git a/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ParserTest.kt b/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ParserTest.kt
index 9037efe..8e0525e 100644
--- a/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ParserTest.kt
+++ b/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ParserTest.kt
@@ -5,6 +5,7 @@ import arrow.core.leftNel
 import arrow.core.right
 import com.sksamuel.tribune.core.strings.minlen
 import com.sksamuel.tribune.core.strings.notBlank
+import com.sksamuel.tribune.core.strings.notNullOrBlank
 import io.kotest.core.spec.style.FunSpec
 import io.kotest.matchers.shouldBe
 
@@ -82,7 +83,7 @@ class ValidatedTest : FunSpec() {
 
          val nameParser: Parser<UpdateRequest, ValidName, String> = Parser<UpdateRequest>()
             .map { it.name }
-            .notBlank { "Name cannot be blank" }
+            .notNullOrBlank { "Name cannot be blank" }
             .minlen(6) { "Name must have 6 characters" }
             .map { ValidName(it) }
 
diff --git a/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ZipTest.kt b/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ZipTest.kt
index 6f8e8cf..8c669ac 100644
--- a/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ZipTest.kt
+++ b/tribune-core/src/test/kotlin/com/sksamuel/tribune/core/ZipTest.kt
@@ -16,16 +16,16 @@ class ZipTest : FunSpec() {
          val p2 = Parser.from<String?>().notNullOrBlank { "bar" }
          val p = Parser.zip(p1, p2)
          p.parse(null) shouldBe nonEmptyListOf("foo", "bar").left()
-//         p.parse("a") shouldBe nonEmptyListOf("Must have length > 2").left()
-//         p.parse("ab") shouldBe Pair("ab", "ab").right()
+         p.parse("a") shouldBe nonEmptyListOf("Must have length > 2").left()
+         p.parse("ab") shouldBe Pair("ab", "ab").right()
       }
 
-      xtest("zip 3") {
+      test("zip 3") {
          val p1 = Parser.from<String?>().notNullOrBlank { "foo" }.minlen(2) { "Must have length > 2" }
          val p2 = Parser.from<String?>().notNullOrBlank { "bar" }
          val p3 = Parser.from<String?>().notNullOrBlank { "baz" }
          val p = Parser.zip(p1, p2, p3)
-//         p.parse(null) shouldBe nonEmptyListOf("foo", "bar", "baz").left()
+         p.parse(null) shouldBe nonEmptyListOf("foo", "bar", "baz").left()
          p.parse("a") shouldBe nonEmptyListOf("Must have length > 2").left()
          p.parse("ab") shouldBe Triple("ab", "ab", "ab").right()
       }