diff --git a/src/core/operations/FromBase91.mjs b/src/core/operations/FromBase91.mjs
index 921434dd..08abb710 100644
--- a/src/core/operations/FromBase91.mjs
+++ b/src/core/operations/FromBase91.mjs
@@ -23,6 +23,17 @@ class FromBase91 extends Operation {
         this.infoURL = "https://en.wikipedia.org/wiki/Binary-to-text_encoding#Encoding_standards";
         this.inputType = "string";
         this.outputType = "ArrayBuffer";
+        this.checks = [
+            {
+                pattern:
+                    "^" +
+                    "[\\s0-9A-Za-z!#$%&()*+,./:;<=>?@\\\[\\\]\\^_`{|}~\"]*" +
+                    "[0-9A-Za-z!#$%&()*+,./:;<=>?@\\\[\\\]\\^_`{|}~\"]{15}" +
+                    "[\\s0-9A-Za-z!#$%&()*+,./:;<=>?@\\\[\\\]\\^_`{|}~\"]*" +
+                    "$",
+                args: []
+            }
+        ];
     }
 
     /**
diff --git a/tests/operations/index.mjs b/tests/operations/index.mjs
index f147e9e7..9b25fb2f 100644
--- a/tests/operations/index.mjs
+++ b/tests/operations/index.mjs
@@ -24,6 +24,7 @@ import "./tests/Base58.mjs";
 import "./tests/Base62.mjs";
 import "./tests/Base64.mjs";
 import "./tests/Base85.mjs";
+import "./tests/Base91.mjs";
 import "./tests/Base92.mjs";
 import "./tests/BCD.mjs";
 import "./tests/BitwiseOp.mjs";
diff --git a/tests/operations/tests/Base91.mjs b/tests/operations/tests/Base91.mjs
new file mode 100644
index 00000000..f75d2b96
--- /dev/null
+++ b/tests/operations/tests/Base91.mjs
@@ -0,0 +1,35 @@
+/**
+ * Base91 tests
+ *
+ * @author ialejandrozalles
+ * @license Apache-2.0
+ */
+import TestRegister from "../../lib/TestRegister.mjs";
+
+TestRegister.addTests([
+    {
+        name: "To Base91",
+        input: "hello",
+        expectedOutput: "TPwJh>A",
+        recipeConfig: [
+            { op: "To Base91", args: [] }
+        ]
+    },
+    {
+        name: "From Base91",
+        input: "TPwJh>A",
+        expectedOutput: "hello",
+        recipeConfig: [
+            { op: "From Base91", args: [] }
+        ]
+    },
+    {
+        name: "To/From Base91 Roundtrip",
+        input: "The quick brown fox jumps over the lazy dog",
+        expectedOutput: "The quick brown fox jumps over the lazy dog",
+        recipeConfig: [
+            { op: "To Base91", args: [] },
+            { op: "From Base91", args: [] }
+        ]
+    }
+]);
diff --git a/tests/operations/tests/Magic.mjs b/tests/operations/tests/Magic.mjs
index 90401dc1..7a7d15d4 100644
--- a/tests/operations/tests/Magic.mjs
+++ b/tests/operations/tests/Magic.mjs
@@ -153,4 +153,16 @@ TestRegister.addTests([
             }
         ]
     }
+    ,
+    {
+        name: "Magic Chain: Base91",
+        input: "xD7ghoHB4!#/Tm_ogr$J9[JTrUJ*|jgSr!=EWoFB",
+        expectedMatch: /From_Base91\(\)/,
+        recipeConfig: [
+            {
+                op: "Magic",
+                args: [3, false, false]
+            }
+        ],
+    }
 ]);