diff --git a/Sources/Fuzzilli/Engines/FuzzEngine.swift b/Sources/Fuzzilli/Engines/FuzzEngine.swift
index 7f5620a8c..1b5a61044 100644
--- a/Sources/Fuzzilli/Engines/FuzzEngine.swift
+++ b/Sources/Fuzzilli/Engines/FuzzEngine.swift
@@ -14,13 +14,27 @@
 
 import Foundation
 
-public protocol FuzzEngine: ComponentBase {
+public class FuzzEngine: ComponentBase {
+    private var postProcessor: FuzzingPostProcessor? = nil
+
+    override init(name: String) {
+        super.init(name: name)
+    }
+
+    // Install a post-processor that is executed for every generated program and can modify it (by returning a different program).
+    public func registerPostProcessor(_ postProcessor: FuzzingPostProcessor) {
+        assert(self.postProcessor == nil)
+        self.postProcessor = postProcessor
+    }
+
     // Performs a single round of fuzzing using the engine.
-    func fuzzOne(_ group: DispatchGroup)
-}
+    public func fuzzOne(_ group: DispatchGroup) {
+        fatalError("Must be implemented by child classes")
+    }
+
+    final func execute(_ program: Program, withTimeout timeout: UInt32? = nil) -> ExecutionOutcome {
+        let program = postProcessor?.process(program, for: fuzzer) ?? program
 
-extension FuzzEngine {
-    public func execute(_ program: Program, withTimeout timeout: UInt32? = nil) -> ExecutionOutcome {
         fuzzer.dispatchEvent(fuzzer.events.ProgramGenerated, data: program)
 
         let execution = fuzzer.execute(program, withTimeout: timeout, purpose: .fuzzing)
@@ -67,7 +81,7 @@ extension FuzzEngine {
         return execution.outcome
     }
 
-    private func ensureDeterministicExecutionOutcomeForDiagnostic(of program: Program) {
+    private final func ensureDeterministicExecutionOutcomeForDiagnostic(of program: Program) {
         let execution1 = fuzzer.execute(program, purpose: .other)
         let stdout1 = execution1.stdout, stderr1 = execution1.stderr
         let execution2 = fuzzer.execute(program, purpose: .other)
diff --git a/Sources/Fuzzilli/Engines/FuzzingPostProcessor.swift b/Sources/Fuzzilli/Engines/FuzzingPostProcessor.swift
new file mode 100644
index 000000000..e0c61f27f
--- /dev/null
+++ b/Sources/Fuzzilli/Engines/FuzzingPostProcessor.swift
@@ -0,0 +1,20 @@
+// Copyright 2023 Google LLC
+//
+// Licensed 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
+//
+// https://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.
+
+import Foundation
+
+// A post-processor can be used to modify samples generated during fuzzing before executing them.
+public protocol FuzzingPostProcessor {
+    func process(_ program: Program, for fuzzer: Fuzzer) -> Program
+}
diff --git a/Sources/Fuzzilli/Engines/GenerativeEngine.swift b/Sources/Fuzzilli/Engines/GenerativeEngine.swift
index 3886a5f00..f2a5115ee 100644
--- a/Sources/Fuzzilli/Engines/GenerativeEngine.swift
+++ b/Sources/Fuzzilli/Engines/GenerativeEngine.swift
@@ -15,7 +15,7 @@
 import Foundation
 
 /// Purely generative fuzzing engine, mostly used for initial corpus generation when starting without an existing corpus.
-public class GenerativeEngine: ComponentBase, FuzzEngine {
+public class GenerativeEngine: FuzzEngine {
     /// Approximate number of instructions to generate in additional to any prefix code.
     private let numInstructionsToGenerate = 10
 
@@ -24,7 +24,7 @@ public class GenerativeEngine: ComponentBase, FuzzEngine {
     }
 
     /// Perform one round of fuzzing: simply generate a new program and execute it
-    public func fuzzOne(_ group: DispatchGroup) {
+    public override func fuzzOne(_ group: DispatchGroup) {
         let b = fuzzer.makeBuilder()
 
         // Start by building a prefix that creates some variables (of known types) that the following CodeGenerators can then make use of.
diff --git a/Sources/Fuzzilli/Engines/HybridEngine.swift b/Sources/Fuzzilli/Engines/HybridEngine.swift
index d735680d4..f25ab27ef 100644
--- a/Sources/Fuzzilli/Engines/HybridEngine.swift
+++ b/Sources/Fuzzilli/Engines/HybridEngine.swift
@@ -14,7 +14,7 @@
 
 import Foundation
 
-public class HybridEngine: ComponentBase, FuzzEngine {
+public class HybridEngine: FuzzEngine {
     // The number of mutations to perform to a single sample per round
     private let numConsecutiveMutations: Int
 
@@ -90,7 +90,7 @@ public class HybridEngine: ComponentBase, FuzzEngine {
         return program
     }
 
-    public func fuzzOne(_ group: DispatchGroup) {
+    public override func fuzzOne(_ group: DispatchGroup) {
         let template = fuzzer.programTemplates.randomElement()
 
         let generatedProgram = generateTemplateProgram(template: template)
diff --git a/Sources/Fuzzilli/Engines/MultiEngine.swift b/Sources/Fuzzilli/Engines/MultiEngine.swift
index b96cead9a..2eab72945 100644
--- a/Sources/Fuzzilli/Engines/MultiEngine.swift
+++ b/Sources/Fuzzilli/Engines/MultiEngine.swift
@@ -17,7 +17,7 @@ import Foundation
 /// Wraps multiple engines into one, which can be initialized given a
 /// WeightedList. This can then switch engines to use, or use a more
 /// complicated heuristic.
-public class MultiEngine: ComponentBase, FuzzEngine {
+public class MultiEngine: FuzzEngine {
     let engines: WeightedList<FuzzEngine>
 
     /// The current active engine.
@@ -43,7 +43,7 @@ public class MultiEngine: ComponentBase, FuzzEngine {
         }
     }
 
-    public func fuzzOne(_ group: DispatchGroup) {
+    public override func fuzzOne(_ group: DispatchGroup) {
         activeEngine.fuzzOne(group)
         currentIteration += 1
         if currentIteration % iterationsPerEngine == 0 {
diff --git a/Sources/Fuzzilli/Engines/MutationEngine.swift b/Sources/Fuzzilli/Engines/MutationEngine.swift
index fc0321ae0..a02176bee 100644
--- a/Sources/Fuzzilli/Engines/MutationEngine.swift
+++ b/Sources/Fuzzilli/Engines/MutationEngine.swift
@@ -15,7 +15,7 @@
 import Foundation
 
 /// The core fuzzer responsible for generating and executing programs.
-public class MutationEngine: ComponentBase, FuzzEngine {
+public class MutationEngine: FuzzEngine {
     // The number of consecutive mutations to apply to a sample.
     private let numConsecutiveMutations: Int
 
@@ -44,7 +44,7 @@ public class MutationEngine: ComponentBase, FuzzEngine {
     ///
     /// This ensures that samples will be mutated multiple times as long
     /// as the intermediate results do not cause a runtime exception.
-    public func fuzzOne(_ group: DispatchGroup) {
+    public override func fuzzOne(_ group: DispatchGroup) {
         var parent = fuzzer.corpus.randomElementForMutating()
         parent = prepareForMutating(parent)
         for _ in 0..<numConsecutiveMutations {
diff --git a/Sources/Fuzzilli/Minimization/PostProcessor.swift b/Sources/Fuzzilli/Minimization/MinimizationPostProcessor.swift
similarity index 100%
rename from Sources/Fuzzilli/Minimization/PostProcessor.swift
rename to Sources/Fuzzilli/Minimization/MinimizationPostProcessor.swift
diff --git a/Sources/Fuzzilli/Util/MockFuzzer.swift b/Sources/Fuzzilli/Util/MockFuzzer.swift
index 3a7493bae..73b6feab3 100644
--- a/Sources/Fuzzilli/Util/MockFuzzer.swift
+++ b/Sources/Fuzzilli/Util/MockFuzzer.swift
@@ -154,8 +154,7 @@ class MockEvaluator: ProgramEvaluator {
 }
 
 /// Create a fuzzer instance usable for testing.
-public func makeMockFuzzer(config maybeConfiguration: Configuration? = nil, engine maybeEngine: FuzzEngine? = nil, runner maybeRunner: ScriptRunner? = nil, environment maybeEnvironment: Environment? = nil,
-                           evaluator maybeEvaluator: ProgramEvaluator? = nil, corpus maybeCorpus: Corpus? = nil) -> Fuzzer {
+public func makeMockFuzzer(config maybeConfiguration: Configuration? = nil, engine maybeEngine: FuzzEngine? = nil, runner maybeRunner: ScriptRunner? = nil, environment maybeEnvironment: Environment? = nil, evaluator maybeEvaluator: ProgramEvaluator? = nil, corpus maybeCorpus: Corpus? = nil) -> Fuzzer {
     dispatchPrecondition(condition: .onQueue(DispatchQueue.main))
 
     // The configuration of this fuzzer.
diff --git a/Sources/FuzzilliCli/Profiles/DuktapeProfile.swift b/Sources/FuzzilliCli/Profiles/DuktapeProfile.swift
index bca397b1a..8d38b9be0 100644
--- a/Sources/FuzzilliCli/Profiles/DuktapeProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/DuktapeProfile.swift
@@ -52,5 +52,7 @@ let duktapeProfile = Profile(
         "Duktape.compact"           :  .function([.object()] => .undefined),
         "placeholder"               :  .function([] => .undefined),
 
-    ]
+    ],
+
+    optionalPostProcessor: nil
 )
diff --git a/Sources/FuzzilliCli/Profiles/JSCProfile.swift b/Sources/FuzzilliCli/Profiles/JSCProfile.swift
index 4e2cbf311..ee6a2f372 100644
--- a/Sources/FuzzilliCli/Profiles/JSCProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/JSCProfile.swift
@@ -113,5 +113,7 @@ let jscProfile = Profile(
         "fiatInt52"           : .function([.number] => .number),
         "forceGCSlowPaths"    : .function([] => .anything),
         "ensureArrayStorage"  : .function([] => .anything),
-    ]
+    ],
+
+    optionalPostProcessor: nil
 )
diff --git a/Sources/FuzzilliCli/Profiles/JerryscriptProfile.swift b/Sources/FuzzilliCli/Profiles/JerryscriptProfile.swift
index 463221f92..3a41c6483 100644
--- a/Sources/FuzzilliCli/Profiles/JerryscriptProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/JerryscriptProfile.swift
@@ -48,5 +48,7 @@ let jerryscriptProfile = Profile(
         "print"             : .function([] => .undefined),
         "resourceName"      : .function([] => .undefined),
         "placeholder"       : .function([] => .undefined),
-    ]
+    ],
+
+    optionalPostProcessor: nil
 )
diff --git a/Sources/FuzzilliCli/Profiles/Profile.swift b/Sources/FuzzilliCli/Profiles/Profile.swift
index 6c1bfc328..105f1541f 100644
--- a/Sources/FuzzilliCli/Profiles/Profile.swift
+++ b/Sources/FuzzilliCli/Profiles/Profile.swift
@@ -35,6 +35,9 @@ struct Profile {
     let disabledMutators: [String]
 
     let additionalBuiltins: [String: JSType]
+
+    // An optional post-processor that is executed for every sample generated for fuzzing and can modify it.
+    let optionalPostProcessor: FuzzingPostProcessor?
 }
 
 let profiles = [
diff --git a/Sources/FuzzilliCli/Profiles/QjsProfile.swift b/Sources/FuzzilliCli/Profiles/QjsProfile.swift
index cfd32405f..90bcbf3d1 100644
--- a/Sources/FuzzilliCli/Profiles/QjsProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/QjsProfile.swift
@@ -45,5 +45,7 @@ let qjsProfile = Profile(
 
     additionalBuiltins: [
         "placeholder"         : .function([] => .undefined)
-    ]
+    ],
+
+    optionalPostProcessor: nil
 )
diff --git a/Sources/FuzzilliCli/Profiles/QtjsProfile.swift b/Sources/FuzzilliCli/Profiles/QtjsProfile.swift
index cb90d3aa1..75955164c 100644
--- a/Sources/FuzzilliCli/Profiles/QtjsProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/QtjsProfile.swift
@@ -57,4 +57,7 @@ let qtjsProfile = Profile(
 
     additionalBuiltins: [
         "gc"                : .function([] => .undefined),
-    ])
+    ],
+
+    optionalPostProcessor: nil
+)
diff --git a/Sources/FuzzilliCli/Profiles/SpidermonkeyProfile.swift b/Sources/FuzzilliCli/Profiles/SpidermonkeyProfile.swift
index 61e03eeb2..081cbd39b 100644
--- a/Sources/FuzzilliCli/Profiles/SpidermonkeyProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/SpidermonkeyProfile.swift
@@ -104,5 +104,7 @@ let spidermonkeyProfile = Profile(
         "drainJobQueue" : .function([] => .undefined),
         "bailout"       : .function([] => .undefined),
 
-    ]
+    ],
+
+    optionalPostProcessor: nil
 )
diff --git a/Sources/FuzzilliCli/Profiles/V8Profile.swift b/Sources/FuzzilliCli/Profiles/V8Profile.swift
index 7fd13d255..5d9ea62bb 100644
--- a/Sources/FuzzilliCli/Profiles/V8Profile.swift
+++ b/Sources/FuzzilliCli/Profiles/V8Profile.swift
@@ -568,5 +568,7 @@ let v8Profile = Profile(
         "gc"                                            : .function([] => (.undefined | .jsPromise)),
         "d8"                                            : .object(),
         "Worker"                                        : .constructor([.anything, .object()] => .object(withMethods: ["postMessage","getMessage"])),
-    ]
+    ],
+
+    optionalPostProcessor: nil
 )
diff --git a/Sources/FuzzilliCli/Profiles/XSProfile.swift b/Sources/FuzzilliCli/Profiles/XSProfile.swift
index 3b5fa5c6e..422ecc42e 100644
--- a/Sources/FuzzilliCli/Profiles/XSProfile.swift
+++ b/Sources/FuzzilliCli/Profiles/XSProfile.swift
@@ -48,5 +48,7 @@ let xsProfile = Profile(
         "gc"                  : .function([] => .undefined),
         "print"               : .function([.string] => .undefined),
         "placeholder"         : .function([] => .undefined),
-    ]
+    ],
+
+    optionalPostProcessor: nil
 )
diff --git a/Sources/FuzzilliCli/main.swift b/Sources/FuzzilliCli/main.swift
index a2dd98794..98a9787ad 100644
--- a/Sources/FuzzilliCli/main.swift
+++ b/Sources/FuzzilliCli/main.swift
@@ -421,6 +421,11 @@ func makeFuzzer(with configuration: Configuration) -> Fuzzer {
         engine = MutationEngine(numConsecutiveMutations: consecutiveMutations)
     }
 
+    // Add a post-processor if the profile defines one.
+    if let postProcessor = profile.optionalPostProcessor {
+        engine.registerPostProcessor(postProcessor)
+    }
+
     // Program templates to use.
     var programTemplates = profile.additionalProgramTemplates
     for template in ProgramTemplates {