diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/validator/ETag.java b/httpclient5/src/main/java/org/apache/hc/client5/http/validator/ETag.java
new file mode 100644
index 000000000..a5b32149c
--- /dev/null
+++ b/httpclient5/src/main/java/org/apache/hc/client5/http/validator/ETag.java
@@ -0,0 +1,191 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+
+package org.apache.hc.client5.http.validator;
+
+import org.apache.hc.core5.annotation.Contract;
+import org.apache.hc.core5.annotation.Internal;
+import org.apache.hc.core5.annotation.ThreadingBehavior;
+import org.apache.hc.core5.http.Header;
+import org.apache.hc.core5.http.MessageHeaders;
+import org.apache.hc.core5.util.Args;
+import org.apache.hc.core5.util.CharArrayBuffer;
+import org.apache.hc.core5.util.LangUtils;
+import org.apache.hc.core5.util.Tokenizer;
+
+/**
+ * Represents ETag value.
+ *
+ * @since 5.4
+ */
+@Contract(threading = ThreadingBehavior.IMMUTABLE)
+public final class ETag {
+
+    private final String value;
+    private final ValidatorType type;
+
+    public ETag(final String value, final ValidatorType type) {
+        this.value = Args.notNull(value, "Value");
+        this.type = Args.notNull(type, "Validator type");
+    }
+
+    public ETag(final String value) {
+        this(value, ValidatorType.STRONG);
+    }
+
+    public ValidatorType getType() {
+        return type;
+    }
+
+    public String getValue() {
+        return value;
+    }
+
+    public static boolean strongCompare(final ETag t1, final ETag t2) {
+        if (t1 == null || t2 == null) {
+            return false;
+        }
+        return t1.type == ValidatorType.STRONG && t1.type == t2.type && t1.value.equals(t2.value);
+    }
+
+    public static boolean weakCompare(final ETag t1, final ETag t2) {
+        if (t1 == null || t2 == null) {
+            return false;
+        }
+        return t1.value.equals(t2.value);
+    }
+
+    static ETag parse(final CharSequence buf, final Tokenizer.Cursor cursor) {
+        final Tokenizer tokenizer = Tokenizer.INSTANCE;
+        tokenizer.skipWhiteSpace(buf, cursor);
+
+        ValidatorType type = ValidatorType.STRONG;
+
+        if (!cursor.atEnd() && buf.charAt(cursor.getPos()) == 'W') {
+            cursor.updatePos(cursor.getPos() + 1);
+            if (!cursor.atEnd() && buf.charAt(cursor.getPos()) == '/') {
+                type = ValidatorType.WEAK;
+                cursor.updatePos(cursor.getPos() + 1);
+            } else {
+                return null;
+            }
+        }
+
+        String value = null;
+        if (!cursor.atEnd() && buf.charAt(cursor.getPos()) == '"') {
+            cursor.updatePos(cursor.getPos() + 1);
+            final StringBuilder sb = new StringBuilder();
+            for (;;) {
+                if (cursor.atEnd()) {
+                    return null;
+                }
+                final char ch = buf.charAt(cursor.getPos());
+                cursor.updatePos(cursor.getPos() + 1);
+                if (ch == '"') {
+                    break;
+                } else {
+                    sb.append(ch);
+                }
+            }
+            value = sb.toString();
+        }
+
+        tokenizer.skipWhiteSpace(buf, cursor);
+        if (!cursor.atEnd()) {
+            return null;
+        }
+
+        return new ETag(value, type);
+    }
+
+    public static ETag parse(final String s) {
+        if (s == null) {
+            return null;
+        }
+        final Tokenizer.Cursor cursor = new Tokenizer.Cursor(0, s.length());
+        return parse(s, cursor);
+    }
+
+    public static ETag parse(final Header h) {
+        if (h == null) {
+            return null;
+        }
+        final String value = h.getValue();
+        if (value == null) {
+            return null;
+        }
+        return parse(value);
+    }
+
+    public static ETag get(final MessageHeaders message) {
+        if (message == null) {
+            return null;
+        }
+        return parse(message.getFirstHeader(HttpHeaders.ETAG));
+    }
+
+    @Internal
+    public void format(final CharArrayBuffer buf) {
+        if (buf == null) {
+            return;
+        }
+        if (type == ValidatorType.WEAK) {
+            buf.append("W/");
+        }
+        buf.append('"');
+        buf.append(value);
+        buf.append('"');
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o instanceof ETag) {
+            final ETag that = (ETag) o;
+            return this.type == that.type && this.value.equals(that.value);
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        int hash = LangUtils.HASH_SEED;
+        hash = LangUtils.hashCode(hash, type);
+        hash = LangUtils.hashCode(hash, value);
+        return hash;
+    }
+
+    @Override
+    public String toString() {
+        final CharArrayBuffer buf = new CharArrayBuffer(64);
+        format(buf);
+        return buf.toString();
+    }
+
+}
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/validator/ValidatorType.java b/httpclient5/src/main/java/org/apache/hc/client5/http/validator/ValidatorType.java
new file mode 100644
index 000000000..eb13960fc
--- /dev/null
+++ b/httpclient5/src/main/java/org/apache/hc/client5/http/validator/ValidatorType.java
@@ -0,0 +1,37 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+
+package org.apache.hc.client5.http.validator;
+
+/**
+ * @since 5.4
+ */
+public enum ValidatorType {
+
+    STRONG, WEAK
+
+}
\ No newline at end of file
diff --git a/httpclient5/src/test/java/org/apache/hc/client5/http/validator/TestETag.java b/httpclient5/src/test/java/org/apache/hc/client5/http/validator/TestETag.java
new file mode 100644
index 000000000..865683094
--- /dev/null
+++ b/httpclient5/src/test/java/org/apache/hc/client5/http/validator/TestETag.java
@@ -0,0 +1,93 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+package org.apache.hc.client5.http.validator;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class TestETag {
+
+    @Test
+    public void testHashCodeEquals() {
+        final ETag tag1 = new ETag("this");
+        final ETag tag2 = new ETag("this");
+        final ETag tag3 = new ETag("this", ValidatorType.WEAK);
+        final ETag tag4 = new ETag("that", ValidatorType.WEAK);
+
+        Assertions.assertEquals(tag1.hashCode(), tag2.hashCode());
+        Assertions.assertNotEquals(tag2.hashCode(), tag3.hashCode());
+        Assertions.assertNotEquals(tag3.hashCode(), tag4.hashCode());
+
+        Assertions.assertEquals(tag1, tag2);
+        Assertions.assertNotEquals(tag2, tag3);
+        Assertions.assertNotEquals(tag3, tag4);
+    }
+
+    @Test
+    public void testToString() {
+        Assertions.assertEquals("\"blah\"", new ETag("blah").toString());
+        Assertions.assertEquals("W/\"blah\"", new ETag("blah", ValidatorType.WEAK).toString());
+        Assertions.assertEquals("\"\"", new ETag("").toString());
+    }
+
+    @Test
+    public void testParse() {
+        Assertions.assertEquals(new ETag("blah", ValidatorType.WEAK), ETag.parse("  W/\"blah\"  "));
+        Assertions.assertEquals(new ETag(" huh?"), ETag.parse("  \" huh?\"   "));
+        Assertions.assertEquals(new ETag(" ", ValidatorType.WEAK), ETag.parse("W/\" \""));
+        Assertions.assertEquals(new ETag(""), ETag.parse("\"\""));
+        Assertions.assertNull(ETag.parse("wrong"));
+        Assertions.assertNull(ETag.parse("w/\"wrong\""));
+        Assertions.assertNull(ETag.parse("W /\"wrong\""));
+        Assertions.assertNull(ETag.parse("W/ \"wrong\""));
+        Assertions.assertNull(ETag.parse("W/wrong"));
+        Assertions.assertNull(ETag.parse("\"cut"));
+        Assertions.assertNull(ETag.parse("    \""));
+        Assertions.assertNull(ETag.parse("W/\""));
+    }
+
+    @Test
+    public void testComparison() {
+        Assertions.assertFalse(ETag.strongCompare(new ETag("1", ValidatorType.WEAK), new ETag("1", ValidatorType.WEAK)));
+        Assertions.assertTrue(ETag.weakCompare(new ETag("1", ValidatorType.WEAK), new ETag("1", ValidatorType.WEAK)));
+        Assertions.assertFalse(ETag.strongCompare(new ETag("1", ValidatorType.WEAK), new ETag("2", ValidatorType.WEAK)));
+        Assertions.assertFalse(ETag.weakCompare(new ETag("1", ValidatorType.WEAK), new ETag("2", ValidatorType.WEAK)));
+        Assertions.assertFalse(ETag.strongCompare(new ETag("1", ValidatorType.WEAK), new ETag("1")));
+        Assertions.assertTrue(ETag.weakCompare(new ETag("1", ValidatorType.WEAK), new ETag("1")));
+        Assertions.assertTrue(ETag.strongCompare(new ETag("1"), new ETag("1")));
+        Assertions.assertTrue(ETag.weakCompare(new ETag("1"), new ETag("1")));
+
+        Assertions.assertFalse(ETag.weakCompare(new ETag("1", ValidatorType.WEAK), null));
+        Assertions.assertFalse(ETag.weakCompare(null, new ETag("1", ValidatorType.WEAK)));
+        Assertions.assertFalse(ETag.weakCompare(null, null));
+
+        Assertions.assertFalse(ETag.strongCompare(new ETag("1"), null));
+        Assertions.assertFalse(ETag.strongCompare(null, new ETag("1")));
+        Assertions.assertFalse(ETag.strongCompare(null, null));
+    }
+
+}