Play Mode · Live C# Patches

Hot Patch

Stop waiting on domain reloads. Edit C# in your IDE during Play Mode and feel the change on the next call - while your scene, timers, and debug setup stay alive.

Milliseconds to iterate. Hours of state preserved.

Get started Asset Store

The Patch Pipeline

From keystroke to gameplay

Save in your IDE. Hot Patch compiles and redirects the live method. Your running scene picks up the change instantly.

Edit jumpForce, then save. Scene state stays untouched.

Play Mode Active

Rider - PlayerController.cs

PlayerController.cs GameManager.cs

public class PlayerController : MonoBehaviour
{
    float jumpForce = 8f;

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
            rb.velocity = Vector2.up * jumpForce;
    }
}

Saved · Ctrl+S

UTF-8 Editing…

Hot Patch

> waiting for save…

> file saved: PlayerController.cs

> compiling diff…

> Harmony patch queued

> patched in 14ms

Game

1920×1080

JumpForce = 8f
Frame: 1840

Patched live

Player

Waiting for patch… 14ms

1 Edit & save

2 Detect

3 Compile & patch

4 Play instantly

Live Demo

Watch Hot Patch in action

See C# edits apply live. No domain reload, no lost Play Mode state.

Watch demo

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No More Waiting

Update your C# methods instantly while the game is running.

0:00 min 1:00 min 2:00 min 3:00 min 4:00 min

Normal Unity Editor

Hot Patch

< 1 second

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Built for faster iteration

Everything you need to keep Play Mode alive while you fix, tune, and prototype.

Edit any function

If you have the C# code, Hot Patch can patch it instantly. Works with Rider, Visual Studio, VS Code, or any editor that saves files.

Easy setup

Import and run. No project changes, attributes, or build steps required to get started.

Works seamlessly

Changes apply without a domain reload. The game keeps running, static state, timers, and scene objects stay intact.

Fast, even on large projects

Changes apply in milliseconds. Roslyn compiles only what changed, not your entire solution.

Battle-tested

Built by game devs, for game devs, an Editor-first workflow designed for day-to-day Unity iteration.

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Get Started In Just a Few Minutes…

1. Download

Download and import the Unity package

2. Start

Open Tools → DivinityCodes → Hot Patch and press Start

3. Run

Enter Play Mode, edit C#, save and enjoy instant patches

Full setup guide →

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Why Hot Patch?

Unity's default workflow interrupts you on every script change. A small fix can cost 30-60 seconds of compile time, and a domain reload wipes the Play Mode state you were debugging.

Without Hot Patch

• Save → wait for compile → domain reload
• Lose running game state on every edit
• Re-test from scratch after each change

With Hot Patch

• Save → patch applies in milliseconds
• Keep Play Mode alive while you iterate
• Re-invoke the changed method and verify instantly

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How it works

1. Enter Play Mode with Hot Patch enabled.
2. Hot Patch blocks Unity's automatic script refresh so saves do not trigger a domain reload.
3. When you save a .cs file, Hot Patch compiles only what changed with Roslyn and redirects method execution with Harmony.
4. The next time your code runs, Update, a button handler, a utility method, it uses the new logic.

No external server. No project setup. Import the package, open the window, press Start, and edit.

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Requirements at a glance

Requirement	Details
Unity Editor	Mono scripting backend
Scope	Play Mode in the Editor
Scripts	Runtime code under Assets/ (not Editor/)
Not supported	IL2CPP player builds / shipped binaries

See Requirements for the full list, or jump to Features to learn what edits are supported.