diff --git a/Sources/Splash/Output/HTMLOutputFormat.swift b/Sources/Splash/Output/HTMLOutputFormat.swift
index 2f2e71f..69f0aa7 100644
--- a/Sources/Splash/Output/HTMLOutputFormat.swift
+++ b/Sources/Splash/Output/HTMLOutputFormat.swift
@@ -27,26 +27,60 @@ public extension HTMLOutputFormat {
     struct Builder: OutputBuilder {
         private let classPrefix: String
         private var html = ""
+        private var pendingToken: (string: String, type: TokenType)?
+        private var pendingWhitespace: String?
 
         fileprivate init(classPrefix: String) {
             self.classPrefix = classPrefix
         }
 
         public mutating func addToken(_ token: String, ofType type: TokenType) {
-            html.append("<span class=\"\(classPrefix)\(type.string)\">\(token.escaped)</span>")
+            if var pending = pendingToken {
+                guard pending.type != type else {
+                    pendingWhitespace.map { pending.string += $0 }
+                    pendingWhitespace = nil
+                    pending.string += token
+                    pendingToken = pending
+                    return
+                }
+            }
+
+            appendPending()
+            pendingToken = (token, type)
         }
 
         public mutating func addPlainText(_ text: String) {
+            appendPending()
             html.append(text.escaped)
         }
 
         public mutating func addWhitespace(_ whitespace: String) {
-            html.append(whitespace)
+            if pendingToken != nil {
+                pendingWhitespace = (pendingWhitespace ?? "") + whitespace
+            } else {
+                html.append(whitespace)
+            }
         }
 
-        public func build() -> String {
+        public mutating func build() -> String {
+            appendPending()
             return html
         }
+
+        private mutating func appendPending() {
+            if let pending = pendingToken {
+                html.append("""
+                <span class="\(classPrefix)\(pending.type.string)">\(pending.string.escaped)</span>
+                """)
+
+                pendingToken = nil
+            }
+
+            if let whitespace = pendingWhitespace {
+                html.append(whitespace)
+                pendingWhitespace = nil
+            }
+        }
     }
 }
 
diff --git a/Sources/Splash/Output/OutputBuilder.swift b/Sources/Splash/Output/OutputBuilder.swift
index 85d10cb..8dcaee9 100644
--- a/Sources/Splash/Output/OutputBuilder.swift
+++ b/Sources/Splash/Output/OutputBuilder.swift
@@ -21,5 +21,5 @@ public protocol OutputBuilder {
     /// Add some whitespace to the builder
     mutating func addWhitespace(_ whitespace: String)
     /// Build the final output based on the builder's current state
-    func build() -> Output
+    mutating func build() -> Output
 }
diff --git a/Tests/SplashTests/Tests/HTMLOutputFormatTests.swift b/Tests/SplashTests/Tests/HTMLOutputFormatTests.swift
index 885b040..7f18b38 100644
--- a/Tests/SplashTests/Tests/HTMLOutputFormatTests.swift
+++ b/Tests/SplashTests/Tests/HTMLOutputFormatTests.swift
@@ -10,6 +10,20 @@ final class HTMLOutputFormatTests: SplashTestCase {
         highlighter = SyntaxHighlighter(format: HTMLOutputFormat())
     }
 
+    func testBasicGeneration() {
+        let html = highlighter.highlight("""
+        public struct Test: SomeProtocol {
+            func hello() -> Int { return 7 }
+        }
+        """)
+
+        XCTAssertEqual(html, """
+        <span class="keyword">public struct</span> Test: <span class="type">SomeProtocol</span> {
+            <span class="keyword">func</span> hello() -&gt; <span class="type">Int</span> { <span class="keyword">return</span> <span class="number">7</span> }
+        }
+        """)
+    }
+
     func testStrippingGreaterAndLessThanCharactersFromOutput() {
         let html = highlighter.highlight("Array<String>")
 
@@ -18,6 +32,14 @@ final class HTMLOutputFormatTests: SplashTestCase {
         """)
     }
 
+    func testCommentMerging() {
+        let html = highlighter.highlight("// Hey I'm a comment!")
+
+        XCTAssertEqual(html, """
+        <span class="comment">// Hey I'm a comment!</span>
+        """)
+    }
+
     func testAllTestsRunOnLinux() {
         XCTAssertTrue(TestCaseVerifier.verifyLinuxTests((type(of: self)).allTests))
     }
@@ -26,7 +48,9 @@ final class HTMLOutputFormatTests: SplashTestCase {
 extension HTMLOutputFormatTests {
     static var allTests: [(String, TestClosure<HTMLOutputFormatTests>)] {
         return [
-            ("testStrippingGreaterAndLessThanCharactersFromOutput", testStrippingGreaterAndLessThanCharactersFromOutput)
+            ("testBasicGeneration", testBasicGeneration),
+            ("testStrippingGreaterAndLessThanCharactersFromOutput", testStrippingGreaterAndLessThanCharactersFromOutput),
+            ("testCommentMerging", testCommentMerging)
         ]
     }
 }