What the FireClient mod is#

FireClient has two parts: a Windows launcher and an in-game client that runs as a Fabric mod for Minecraft Java Edition 1.21.1. The mod adds the FireClient menu, the HUD and its modules. It appears in the launcher's Library page next to your other mods, with an on/off switch.

How to get it#

1. Download the launcher from the FireClient download page and compare the SHA-256 when one is shown.
2. Sign in with Microsoft, or use an offline profile.
3. Choose Fabric 1.21.1 and press Play.
4. In a world, press Right Shift to open the FireClient menu.

The install guide has the full steps with screenshots.

What it adds#

• A menu with Mods, Settings, Keybinds and Mod List tabs, and filters such as HUD, PvP, Visual, Move and Perf.
• HUD elements you can switch on and drag into place. See the HUD setup guide.
• Profiles, such as Default, PvP, Builder and Performance.

See more in the screenshots.

Looking for the other FireClient mod?#

A separate Fabric utility mod with a similar name is listed on Modrinth. It is aimed at SMP servers, it is a different project, and it is not affiliated with this site. If that is the one you want, use its own page for downloads and supported versions.

Limits to know about#

• Windows 10 and 11 (64-bit) only for now.
• The in-game mod is built for Minecraft 1.21.1 on Fabric. Other versions can be launched without it.
• FireClient is in early access, and the installer is not code-signed yet. Read Is FireClient safe? before you install.

The short answer#

• Pick Lunar Client if you use macOS or Linux, or you want a long-established client.
• Pick FireClient if you are on Windows 10 or 11, play Minecraft Java 1.21.1 on Fabric, and want a launcher with a built-in Modrinth mod manager and a draggable HUD in one free install.

At a glance#

FireClient (early access, checked October 2026)

• Free Windows 10 and 11 (64-bit) launcher with a Fabric in-game client for Minecraft Java Edition 1.21.1.
• Built-in Modrinth mod browser, your own jar files, a worlds library and a resource pack library.
• Draggable HUD with 11 elements (FPS, CPS, keystrokes, armor, effects and more) and 3 accent themes.
• Early access beta. The installer is unsigned, so Windows SmartScreen may warn about it.
• Needs your own Minecraft Java Edition account to play online; an offline profile is available.

Lunar Client (from its official FAQ, read 27 October 2026)

• Described there as completely free to use.
• Supports Windows, macOS and Linux.
• You sign in with a Microsoft account that owns Minecraft.
• Check Lunar Client's own site for the Minecraft versions it supports today, because that list changes.

Choose Lunar Client if#

• You are not on Windows.
• You want the client that most players and servers already know.
• You need a version that FireClient's in-game client does not cover.

Choose FireClient if#

• You are on Windows 10 or 11 and play Minecraft 1.21.1 with Fabric.
• You want to browse and install Modrinth mods from the same app you launch the game from. See how to install Fabric mods from Modrinth.
• You like arranging your own HUD. See the HUD setup guide.

What FireClient does not do yet#

• No macOS or Linux build.
• The in-game client targets Minecraft 1.21.1 on Fabric. Other versions can be launched without the FireClient mod.
• It is a beta, and we have not published performance benchmarks, so we make no speed claims against any other client.
• The installer is unsigned. Check your download before you run it.

How to decide#

Write down your operating system, your Minecraft version and whether you want mods. Then use our launcher checklist. If FireClient fits, the install guide takes five steps and the download page shows the current version and checksum.

Sources and method: Lunar Client details come from its official FAQ (lunarclient.com/faq). FireClient details come from this site and the release page. FireClient and Lunar Client are independent products; we are not affiliated with Lunar Client. This page will be updated when either product changes.

What is new in FireClient 1.1#

1. Universal Screen Scaling & Device Support#

Whether you are playing on a 1366x768 / 1280x720 laptop screen, a 1080p desktop, or a 4K high-DPI gaming display, FireClient 1.1 automatically scales its interface:

• Dynamic Per-Monitor V2 DPI awareness prevents blurry text and oversized windows.
• Adaptive layout constraints ensure buttons, version pickers, and sidebar navigation never clip or overflow on small displays.
• High-resolution asset rendering for sharp visuals on 1440p and 4K displays.

2. Pro Crash Reporter & 1-Click Auto-Fix#

When Minecraft or a mod encounters an error, FireClient now presents a dedicated Crash Dialog instead of an unexpected exit:

• Automatic root cause diagnostics parsing crash reports and logs.
• Identifies mismatched mod builds, outdated OpenGL drivers, or insufficient memory.
• 1-Click Auto-Fix & Restart: Quarantines conflicting mods and applies safe graphics defaults to get you back in game immediately.
• Real-time hardware summary showing active CPU, GPU, and system RAM.

3. Potato PC & Hardware Optimizer#

Integrated performance optimizations for Intel HD/UHD and AMD Radeon processors:

• Fast graphics profiles and optimized render distances for budget laptops.
• Smart JVM garbage collection flags (-XX:+UseG1GC) for stutter-free gameplay.
• Tailored OpenGL workarounds for legacy integrated graphics chips.

4. Offline Mode Without WiFi#

FireClient now fully supports launching guest and offline profiles without an internet connection. Play offline anywhere with zero network timeouts.

5. License and safety facts#

We have published a plain-language license and safety facts page. It makes no guarantees and does not claim an independent audit:

• The installer is still unsigned, so Windows may warn about it. Check the SHA-256 on the download page when one is shown.
• Microsoft sign-in tokens are stored encrypted with Windows DPAPI under your Windows user account, according to the maintainers.
• The maintainers state that FireClient does not send your tokens or passwords to any FireClient server.

Getting the update#

Existing users can download the update from the Download page or GitHub Releases. Read the license and safety facts or join our Discord for help.

The one rule#

Do not open a world in an older version than the one that last saved it. Newer versions change how worlds are stored, and an older version may fail to load it or corrupt it. Minecraft shows a warning in many cases, so read it and back out.

1. Back up first#

Close the game and back up your worlds. Copy the world folder somewhere safe before you try any version change.

2. Use a separate profile#

Create a new profile for the version you want, instead of changing your main one. In the FireClient launcher the Minecraft version and loader are set per profile, so keep one profile per version and loader.

3. Match Java to the version#

Different Minecraft versions need different Java versions. Minecraft 1.21.1 needs Java 21. Older versions may need an older Java. Check with the Java version checker and the Java 21 guide.

4. Match your mods#

Mods are built for one Minecraft version and one loader. When you switch versions, install the versions of the mods that match. See the mods guide and the loader comparison.

5. Test with a copy#

Make a copy of the world, put the copy in the older version's saves folder and try it there. Keep the original untouched.

Updating to a newer version#

Back up, make a new profile for the new version and open a copy of your world first. Check that your mods have updated before you move your main profile.

If something breaks#

Restore your backup and use the crash checklist. Ask in the FireClient Discord and never post account files or tokens.

Change the skin on your account#

1. Sign in at minecraft.net with the Microsoft account that owns Minecraft Java Edition.
2. Open your profile and find the skin section.
3. Upload a skin file. It must be a PNG, normally 64 by 64 pixels.
4. Choose the arm model, classic (wider arms) or slim (narrower arms), to match your skin.
5. Save, then restart the game or rejoin the server.

If the skin does not change#

• Wait a minute and restart the game, because servers and caches update slowly
• Check that you signed in with the right account, see the sign-in guide
• Check the file is a valid PNG and not a renamed image
• Try the other arm model if the arms look wrong

Local skins in a launcher#

A launcher can also keep skins on your PC. FireClient lists local skins among its features, and they are stored on your computer. A local skin is only for you, so other players on a server will not see it. To change what others see, change the skin on your account.

Where to get skins#

Make your own with a skin editor, or use skins from sites whose terms allow it. Only download image files (.png) and never run an .exe that claims to be a skin, as explained in the safe mods checklist.

Keep your account safe#

Never share your password or access tokens with a site that offers to apply a skin for you. Upload skins only on minecraft.net or in a launcher you trust.

1. Plug in#

Many laptops slow down on battery. Plug in the charger before you play.

2. Use a high-performance power mode#

Open Windows Settings, System, Power (or Power and battery) and choose the best performance mode while plugged in.

3. Make sure the right graphics chip is used#

Laptops with two graphics chips can run Minecraft on the weaker one by mistake. Open Windows Settings, System, Display, Graphics, add the Java program your launcher uses (often javaw.exe), choose Options and set it to High performance. Then restart the game.

4. Use Java 21 and sensible memory#

Minecraft 1.21.1 needs Java 21, see the Java 21 guide. Many laptops have 8 GB of RAM, so around 3 to 4 GB for the game is usually enough. Use the RAM calculator.

5. Lower the heavy settings#

Reduce render distance and simulation distance, use Fast graphics and minimal particles. The video settings generator gives starting values for a low-end or mid-range PC.

6. Add performance mods#

Fabric optimisation mods from Modrinth can raise frame rates a lot on laptops. Follow the mods guide and the FPS guide.

7. Keep it cool#

A hot laptop slows itself down. Use it on a hard surface, clean the vents and avoid blocking airflow.

8. Close other programs#

Browsers with many tabs, recorders and overlays compete for memory and the graphics chip.

Measure the change#

Turn on an FPS counter in the FireClient HUD, write down the number before you change anything and check it after each step.

The short version#

• Fabric is lightweight and quick to support new Minecraft versions. It has a large scene of performance and quality-of-life mods.
• Forge is the long-established loader with a very large library of older and large-scale mods.
• NeoForge began as a fork of Forge and is the Forge-style option that is actively developed for newer versions.
• Quilt is a fork of Fabric that can run many Fabric mods, with a smaller community.

How to choose#

1. Start from the mods you want. Open the mod's page on Modrinth and see which loaders and versions it lists for 1.21.1. The loader is decided by the mod, not the other way round.
2. Do not mix loaders. A Fabric mod will not load on Forge or NeoForge, and the reverse is also true.
3. Pick Fabric for performance and light setups. Fabric is the usual base for frame-rate and utility mods. See the FPS guide.
4. Pick Forge or NeoForge for big content mods. If the mods you want are large content packs that only support those loaders, use the loader they require.

What about performance?#

The loader matters less than the mods you run and your settings. A light Fabric setup with a few optimisation mods often feels smooth on modest PCs, but a heavy list of mods will be demanding on any loader. Use the RAM calculator to pick a memory setting.

Which one does FireClient use?#

The FireClient in-game client is built for Minecraft 1.21.1 on Fabric with Java 21. You can still launch other versions without the FireClient mod. The mods guide shows how to pick the right files, and the explainer covers launchers, loaders and clients.

Quick rules#

• One loader per profile
• Install the loader's API mod if the mods ask for it, such as Fabric API
• Keep separate profiles for separate loaders
• Back up your worlds before changing loaders

If you are joining a server#

1. Check the address and port. A typo is the most common cause. If the server uses a port other than 25565, add it after a colon.
2. Check the version. Your game must match the server. For 1.21.1, use a 1.21.1 profile, and check the server's required version.
3. Check that the server is online. Ask the owner, or check the server's website or Discord.
4. Restart your router and PC. This clears many network glitches.
5. Turn off VPN or proxy. Try again without them.
6. Check Windows Firewall and security software. Make sure Java is allowed.
7. Try another network. A phone hotspot shows whether your home network or school network is the problem.
8. Check mods. A mod that changes networking can break joining. Test with a clean profile, as in the crash checklist.
9. Check whitelist and bans. Some servers only accept listed players.

If you host the server#

• Join localhost first. If that fails, the server is not running correctly.
• Forward TCP 25565 to the PC, allow Java in the firewall, and check you are using your public IP address.
• If your provider uses CGNAT, port forwarding cannot work.

The full steps are in the Paper server guide.

Read the error text#

"Connection refused" means something answered but did not accept, which often points to a wrong port or a server that is not running. "Timed out" means nothing answered, which often points to a firewall, router or wrong address.

Get help#

Ask in the FireClient Discord and share only the error text. Never post tokens, account files or your router login.

1. Check the basics#

You need Java 21 (see the Java 21 guide), enough free memory for the server plus the game, and a PC that stays on while friends play.

2. Start the server once#

Start the Paper server from your launcher or by running the Paper jar. The first run creates the server files. Minecraft's EULA must be accepted before a server will run. If your launcher does not ask, read the EULA, then open eula.txt in the server folder and set eula=true.

3. Join it yourself#

Start Minecraft 1.21.1 and join localhost. If that works, the server itself is fine.

4. Let friends connect from the internet#

Friends outside your home network need your router to send traffic to your PC.

• Give your PC a fixed local address in your router settings
• Forward TCP port 25565 to that address
• Allow Java through Windows Firewall when Windows asks
• Share your public IP address only with people you trust

If your internet provider shares one public address between many customers (CGNAT), port forwarding will not work. Ask your provider or use a hosting service instead.

5. Keep it private and safe#

• Keep online-mode=true in server.properties, so only real accounts can join
• Turn on the whitelist with white-list=true, then add friends with /whitelist add name
• Keep Paper updated and install only plugins you trust
• Do not expose admin or remote-control ports to the internet

6. Protect the world#

Back up your world before changing plugins or versions. Lower the view distance in server.properties if the PC struggles, and see the FPS guide for game-side tips.

If friends cannot connect#

Use the connection timed out checklist. Ask for help in the FireClient Discord and never post your router login or account tokens.

1. Check your internet and service status#

Make sure other sites load. If they do, check the Xbox service status page, because Minecraft sign-in uses Microsoft, Xbox and Minecraft services and an outage there is not something you can fix.

2. Fix your date and time#

Open Windows Settings, Time and language, Date and time, and turn on automatic time and time zone. A wrong clock can make secure sign-in fail.

3. Confirm the account owns Minecraft Java Edition#

To play online you need your own Minecraft Java Edition account. Sign in at minecraft.net with the same Microsoft account and check that Java Edition is on it. A different account from the one you bought with is a common cause. See the Java vs Bedrock guide if you are not sure which edition you own.

4. Check family settings for child accounts#

Child accounts need an adult in the Microsoft family group to allow online play and multiplayer. Ask the family organiser to review the account's Xbox privacy and family settings.

5. Sign out and sign back in#

Remove the account in your launcher, close it and add it again. Then restart the launcher and try once more.

6. Turn off VPN or proxy#

Try without a VPN or proxy, because they can block or change sign-in requests.

7. Test your Microsoft account in a browser#

Sign in at account.microsoft.com. If the password, two-step check or a security prompt fails there, fix that first.

8. Update the launcher#

Install the latest version from the official download page. The launcher fix guide covers problems that stop it from starting.

Stay safe#

• Enter your password only on a genuine Microsoft sign-in page
• Never share access tokens, account files or your launcher data folder
• Be wary of anyone offering to "fix" sign-in by asking for your login
• FireClient says it keeps account token data locally in protected form, and the Terms and Privacy notice explains what is sent to Microsoft

If it still fails, ask in the FireClient Discord and describe the error without posting tokens or logs with personal paths.

1. Use a trusted platform#

Download from a well-known mod platform such as Modrinth rather than a random link from a video description, a chat message or a file-sharing site. The mod manager in FireClient can browse Modrinth directly.

2. Remember what a mod file looks like#

A Fabric mod is a .jar file that goes in your mods folder. A mod is not an installer. If something calls itself a mod but you have to run an .exe, a .bat or a .msi, do not run it.

3. Check version and loader#

Open the Versions tab and filter for Minecraft 1.21.1 and Fabric. The mods guide shows how. A wrong version is the most common reason for a crash.

4. Read the project page#

Look for a clear description, a source code link, an issue tracker, recent updates and a reasonable number of downloads. A page with no description, copied text or only a download button is a warning sign.

5. Check the dependencies#

Many mods need Fabric API or another mod. Install only the required ones the page lists.

6. Be careful with unknown authors#

For a new or unknown author, read comments and issues and start with well-known mods first.

7. Test and keep a backup#

Add one mod at a time and back up your worlds before big changes. If the game crashes, use the crash checklist.

If something looks wrong#

If you ran a file you now doubt, run a scan with Windows Security, change your Microsoft account password and review your account activity. Never share access tokens or account files with anyone.

1. Aim for steady frames#

A high, stable frame rate helps more than a high peak. Lower render distance to around 8 to 12 chunks, turn off fancy graphics and reduce particles. The FPS guide covers memory, Java 21 and Fabric performance mods.

2. Use raw mouse input#

In Options, Controls, Mouse Settings, turn on Raw Input so the game reads your mouse directly. Then set sensitivity to something you can repeat, and keep it the same across sessions.

3. Pick a comfortable field of view#

A wider FOV shows more of the fight, and a narrower one makes targets larger. Test a few values and keep the one you aim best with.

4. Limit visual noise#

Turn off clouds, lower biome blend and keep particles minimal, so fast action is easy to read.

5. Build a clean HUD#

Show only what you use. FPS and coordinates are common choices, and too many elements crowd the screen. In FireClient you can drag each HUD element where you want it and keep the rest off. Back up your layout once you are happy.

6. Check your connection and PC#

Close background apps, use a wired connection if you can and check your ping on the server you play on.

7. Follow the server's rules#

Some servers restrict certain client features or mods. Read the rules before you join and use only what is allowed. No setting replaces practice, and these changes just remove avoidable obstacles.

1. Restart and try again#

Close the launcher, restart your PC and open it once. A leftover background process from an earlier crash is a common cause.

2. End a stuck process#

Press Ctrl + Shift + Esc to open Task Manager. If you see the launcher listed, right-click it and choose End task, then open it again.

3. Check that the file is not blocked#

Right-click the installer or the launcher file, choose Properties and look for an Unblock checkbox near the bottom of the General tab. Tick it and press OK. Only do this for a file you downloaded from an official source, and verify it first with the steps in the safety guide.

4. Look at SmartScreen and antivirus#

Windows SmartScreen or your antivirus can stop an unsigned installer from running. The FireClient early access installer is unsigned, so a prompt is expected. If you have verified the SHA-256 and downloaded from the official page, you can choose to run it. If you are not sure, do not run it.

5. Check your system#

FireClient needs Windows 10 or 11 (64-bit). Make sure Windows is up to date and you have free disk space.

6. Reinstall cleanly#

Uninstall the launcher in Windows Settings, restart, download a fresh copy from the official download page and install again. Your worlds are not stored in the installer folder, but back up your worlds first to be safe.

7. Ask for help#

If it still fails, ask in the FireClient Discord. Say your Windows version and what happens when you click. Never post account files or access tokens.

Launcher#

A launcher is the program that signs you in, picks a game version and starts Minecraft. It also manages profiles, memory settings and game files. The standard Minecraft Launcher is one example, and FireClient includes a launcher too.

Mod loader#

A mod loader is software that lets Minecraft load mods. Fabric is a lightweight mod loader that is popular for fast updates to new Minecraft versions. Other loaders include Forge, NeoForge and Quilt. A mod must be built for the loader you use.

Mod#

A mod is a file that changes or adds something to the game, such as better performance or a new interface. Mods are usually shared on sites like Modrinth. See the mods guide for how to pick the right file.

Client#

A client is a package of features that runs inside the game, often for quality-of-life and display tweaks. Examples include a customisable HUD with FPS, coordinates and other readouts, or a menu to switch settings. A client is built on top of a mod loader.

How FireClient fits#

FireClient combines a launcher with a Fabric client. The launcher starts Minecraft Java Edition on Windows, and the in-game client adds a draggable HUD and a menu that opens with Right Shift, for Minecraft 1.21.1 on Fabric with Java 21. Set up the HUD in the HUD guide.

One more thing#

Some servers have rules about which client features are allowed. Read a server's rules before you join, and respect them.

1. Close the game#

Quit Minecraft completely so no files are being written. Copying a world while the game is open can produce a damaged backup.

2. Find your saves folder#

In the standard Minecraft setup, worlds are in %appdata%\.minecraft\saves. Paste that into the File Explorer address bar and press Enter. Each folder inside is one world. A launcher that uses a different game folder will show its own saves folder, so check your launcher's settings. The worlds library in FireClient lists your worlds with an icon, save date and size, which helps you pick the right one.

3. Copy the world#

Right-click the world folder, choose copy, and paste it somewhere else, such as Documents. For a smaller file, right-click the copy and choose Send to, Compressed (zipped) folder.

4. Name it with the date#

Rename the backup with the world name and date, for example Survival-2026-10-17. Keep a few older copies, not only the latest one.

5. Keep one copy off your PC#

Put a copy on an external drive or in cloud storage, so a dead drive does not take both copies.

When to back up#

• Before installing or removing mods
• Before updating Minecraft or changing the Fabric version
• Before testing a large build or redstone project

How to restore#

Close the game, delete or rename the broken world folder in saves, then paste your backup folder in its place. Open the game and the world appears in the list.

For settings rather than worlds, see how to back up your FireClient HUD layout.

1. Check your current Java version#

Press the Windows key, type cmd and open Command Prompt. Type java -version and press Enter. If the first line shows a version that starts with 21, you are ready. If it shows 8, 11 or 17, or says Java is not recognised, continue.

2. Download Java 21#

Download a Java 21 build for Windows x64 from a trusted vendor. Eclipse Temurin and the Microsoft Build of OpenJDK are common choices. Pick the JDK or JRE 21 installer (.msi) and avoid unknown download sites.

3. Install it#

Run the installer. If it offers options such as adding Java to PATH or setting JAVA_HOME, enable them. Finish the install.

4. Check again#

Close Command Prompt, open a new one and run java -version. It should now show version 21.

5. Restart your launcher#

Close and reopen your launcher so it picks up the new Java. In FireClient, start the Minecraft 1.21.1 Fabric profile and check that it opens.

Common problems#

• Still shows an old version. Another Java install is earlier in your PATH. Uninstall the old one in Windows Settings, then check again.
• "Java not found". Reinstall and make sure the PATH option was enabled.
• Game still crashes. Follow the crash checklist.

Always download installers from the vendor's official site and never from a video description or file-sharing link. The safety guide explains how to verify a file with SHA-256.

1. Check your Java version#

Minecraft 1.21.1 needs Java 21. Open Command Prompt and type java -version. If it shows an older version, follow the Java 21 guide.

2. Remove the last mod you added#

Move the newest mod out of your mods folder and launch again. If the game starts, that mod was the cause. Look for a newer file that supports 1.21.1.

3. Check every mod's version and loader#

Each mod must list Minecraft 1.21.1 and Fabric. Files for Forge, NeoForge, Quilt or a different Minecraft version will not load. The Modrinth mods guide shows how to filter for the right file.

4. Make sure Fabric API is installed#

Many mods need Fabric API. If a crash report says a dependency is missing, install the version that matches 1.21.1.

5. Test with no mods#

Launch a clean 1.21.1 Fabric profile with only Fabric API. If that works, add mods back one at a time.

6. Review your memory setting#

Too little memory can crash heavy mod setups, and a huge value can also cause trouble on low-RAM PCs. Around 4 GB is a safe starting point for most Fabric setups. See the RAM guide.

7. Update your graphics driver#

Crashes on startup that mention graphics or OpenGL are often fixed by updating your GPU driver from the manufacturer.

8. Read the crash report#

Minecraft writes a crash report when it fails. In the standard setup it is saved in the crash-reports folder inside your game folder. Look near the top for the mod name and for lines starting with "Caused by".

Ask for help the safe way#

Share only the relevant part of the report in the FireClient Discord. Never post account files, access tokens or unredacted logs that contain personal paths.

Quick comparison#

• Platforms. Java runs on Windows, macOS and Linux. Bedrock runs on Windows, consoles, phones and tablets.
• Mods. Java has a large mod scene through loaders such as Fabric and Forge. Bedrock uses add-ons and Marketplace content instead of mods.
• Servers. Java has a huge community-server scene, including servers built on Paper. Bedrock has its own server ecosystem and featured servers.
• Cross-play. Bedrock players can usually play with friends across consoles, phones and PC. Java players play with other Java players.
• Launcher. Java starts from a launcher, which is where tools such as FireClient come in. Bedrock on Windows starts from its own app.

How to tell which one you own#

Java Edition starts from the Minecraft Launcher and shows a Java Edition title. Bedrock Edition on Windows starts from the Microsoft Store app. If you bought the PC version, check your Microsoft account, because the PC purchase often includes both editions.

Which should you pick?#

Pick Java if you want mods, custom launchers, the classic server scene or a customisable HUD. Pick Bedrock if you play on a console or phone, or want cross-play with friends on other devices. You can own both and switch.

Where FireClient fits#

FireClient is for Java Edition on Windows 10 and 11. It does not run on Bedrock, MCPE, phones, consoles, macOS or Linux, as explained in the Bedrock and MCPE guide. If you play Java on a Windows PC, start with the install guide.

1. A trustworthy download#

Look for an official site, a public release page and a published checksum. Be careful with launchers shared through video descriptions or reupload sites. Our own safety guide shows how to verify an installer.

2. Real account handling#

A launcher should let you sign in with your own Microsoft account for online play, and should be clear about what it stores. Avoid anything that asks you to paste access tokens.

3. Mod and version management#

Check whether it supports the loader you use (Fabric, Forge and others), whether it can browse Modrinth, and whether it keeps separate profiles so one broken mod does not ruin everything.

4. Memory and performance controls#

You should be able to set the memory budget without editing command lines. See the RAM guide for sensible numbers.

5. Worlds, resource packs and backups#

A good launcher shows your worlds and helps you keep them safe when you update or uninstall.

6. Honest limits#

Read what the project says it cannot do yet. Marketing that promises everything is a warning sign.

Where FireClient fits#

FireClient is a free launcher for Minecraft Java Edition on Windows 10 and 11, with a Fabric in-game client for 1.21.1. It has a draggable HUD with 11 elements, 3 accent themes, a Modrinth mod manager, a worlds library, a memory setting, local skins and Paper server hosting.

It is also early access. The installer is unsigned, the in-game mod covers Minecraft 1.21.1 on Fabric only, and the crosshair editor and cosmetics are planned but not built. The full version is planned for November 2026 with no exact date yet. If that suits you, the download page has the installer, or read the early access details first.

Comparing with a specific client? Read FireClient vs Lunar Client.

What you need#

• Minecraft Java Edition 1.21.1
• The Fabric loader for 1.21.1
• Fabric API, which many mods require

Pick the right file on Modrinth#

On a mod page at Modrinth, open the Versions tab and filter by 1.21.1 and Fabric. A file for another Minecraft version or another loader (Forge, NeoForge, Quilt) will not load on your setup. Read the dependencies list on the page and install anything marked required.

Install with the FireClient mod manager#

The FireClient launcher has a mods page with Modrinth browsing, your own jar files, and curated packs for Performance, Visuals, Utility and PvP. Use it to add mods to your Minecraft 1.21.1 Fabric profile so the files land in the right folder. Make sure the profile is set to 1.21.1 Fabric before you add anything. See the install guide if you have not set up the launcher yet.

Install one at a time#

Add one mod, launch the game, and check that it opens. Then add the next. When something crashes, you know which mod caused it. Installing twenty at once and guessing is the slow way.

Fix a crash#

• Remove the last mod you added and start again
• Check that every mod lists 1.21.1 and Fabric, and that Fabric API is present
• Read the crash report for the mod name near the top, and look for a missing dependency
• Ask in the FireClient Discord and share only the relevant part of the log, never account files or tokens

Protect your worlds#

Mods can change how a world is saved. Make a copy of important worlds before you try a large new set of mods. For better frames, pair this with the FPS guide.

1. Measure first#

Turn on the FPS element on your FireClient HUD and play the same world for a few minutes before you change anything. Write the number down. Without a baseline you cannot tell what worked.

2. Lower the distance settings#

Render distance and simulation distance have the biggest effect on most PCs. Try 10 to 12 chunks for render distance, and 6 to 8 for simulation distance, then raise them if you have headroom. Fancy graphics, smooth lighting and high particle settings cost frames too.

3. Set sensible memory#

More RAM is not always faster. For Fabric with performance mods, around 4 GB is a comfortable start. Our RAM guide explains how to pick a number and where to set it in the launcher.

4. Use Java 21#

Minecraft 1.21.1 runs on Java 21. An old Java runtime can cause slower performance or refuse to start the game at all.

5. Add performance mods from Modrinth#

Fabric has well-known optimisation mods on Modrinth, including Sodium for rendering, Lithium for game logic and FerriteCore for memory use. Always open the mod page and check that it lists Minecraft 1.21.1 and Fabric before you install it. The FireClient launcher has a mod manager with Modrinth support and a curated Performance pack. The mods guide shows the steps.

6. Close what you do not need#

Browsers with many tabs, screen recorders and overlays compete for memory and GPU time. Close them while you test, and make sure your laptop is plugged in and not on a battery saver plan.

7. Compare and keep what works#

Check your FPS number again after each change. If something made no difference or caused crashes, undo it. Results depend heavily on your CPU, GPU and the mods you run, so treat the numbers here as a starting point, not a promise.

What FireClient supports today#

• Minecraft Java Edition on Windows 10 and 11
• The in-game client (HUD and menu) for Minecraft 1.21.1 on Fabric with Java 21
• Other Java versions can be launched, but they run without the FireClient mod

What it does not support#

• Bedrock Edition on Windows, Xbox, PlayStation or Switch
• MCPE and Minecraft on Android or iOS
• macOS and Linux (the launcher is Windows only for now)

How to tell which edition you own#

Java Edition starts from the Minecraft Launcher and has a "Java" title. Bedrock Edition on Windows starts from the Microsoft Store app. If you bought Minecraft for Windows from the Microsoft Store as a single "Bedrock" game, check your Microsoft account for Java Edition as well, because many accounts include both.

Where to go next#

If you play Java Edition on a Windows PC, start with the install guide or the download page. For Bedrock or mobile, you need a different tool. We would rather say so than send you to an installer that will not work for you. Current limits are listed on the early access page.

Official sources only#

Download FireClient from fireclient.net or from the official GitHub Releases page. If a file comes from a video description, a random mirror or a Discord direct message, do not run it. Links on this site point to the GitHub release file.

Why Windows may show a warning#

The current early access installer is unsigned. We do not have a paid code-signing certificate yet, so Windows SmartScreen can show a prompt for an app it does not recognise. That prompt is expected for a new unsigned installer. It does not prove the file is safe, and it does not prove it is unsafe. It means Windows has no reputation data for it yet.

Check the SHA-256 yourself#

A hash is a fingerprint of a file. If your copy has the same SHA-256 as the one published on the download page, the file was not changed on the way to you. In PowerShell:

Get-FileHash .\FireClient-Setup.exe -Algorithm SHA256

Compare the result with the hash shown on the download page. If they differ, delete the file and download it again from an official source.

Check the installer signature#

A code signature shows who signed a file and that it was not changed after signing. It does not show that the software is safe. The download panel shows the current status, and you can check it yourself. In PowerShell:

Get-AuthenticodeSignature .\FireClient-Setup.exe | Format-List Status, StatusMessage, SignerCertificate

• NotSigned: there is no signature. This is the case for the current early access build.
• Valid: signed with a certificate Windows trusts.
• UnknownError with a message about a root certificate that is not trusted: typical for a self-signed certificate. Windows does not trust those by default, so SmartScreen can still warn. If we publish a thumbprint, it should match the one in the file's Properties, Digital Signatures tab.
• HashMismatch: the file changed after it was signed. Do not run it.

You can also right-click the file, choose Properties and open the Digital Signatures tab.

Good habits for any Minecraft client#

• Never paste your Microsoft or Minecraft access token, account files or unredacted logs into a public chat
• Read what the app asks permission for, and read the Terms and Privacy notice
• Keep a backup of worlds you care about before changing game files
• Scan the file with Windows Security or your own antivirus if you want another opinion

What FireClient needs from you#

To play online you need your own Minecraft Java Edition account. FireClient does not give you the game for free. See the install guide for the full steps, and ask in the Discord if something looks wrong.

What you can use today#

Early access includes the launcher for Minecraft Java Edition and the Fabric in-game client for Minecraft 1.21.1:

• A draggable HUD with eleven elements and three accent themes
• A Modrinth mod manager, with room for your own jar files
• A worlds library that shows each world's icon, last-saved date and size
• A memory setting that is passed to Java as the max heap
• Local skins, and a Paper server you can run from the launcher

What is planned#

A crosshair editor and cosmetics are planned but not built yet. They are not part of early access.

Full version in November 2026#

The full version is planned for November 2026. We do not have an exact release day to share yet, and plans can change, so we will confirm the date on the early access page, in the Discord and in the RSS feed before it happens.

How to follow along#

Join the FireClient Discord for questions and bug reports, subscribe to the RSS feed, or add a November reminder from the early access page. If you have not tried it yet, download FireClient.

Quick starting points#

These are rules of thumb, not guarantees. Mods, shaders and view distance change the picture.

• Vanilla Minecraft 1.21: 2 to 4 GB is usually enough
• Performance mods on Fabric: 4 GB is a comfortable start
• Large modpacks or heavy shaders: 6 to 8 GB, raised only if you actually run out

Do not give it everything#

Leave at least 2 to 4 GB for Windows and your other apps. If your PC has 8 GB in total, 4 GB for Minecraft is a sensible ceiling. Asking for more than your system can spare pushes memory onto the disk, which is slower than a smaller allocation.

Set it in FireClient#

In the launcher settings, choose a memory budget. FireClient passes it to Java as the maximum heap and limits it to a safe range, so an extreme value cannot be set by mistake.

Signs you need more, or less#

• Crashes with an out-of-memory error, or stutters that get worse over time: raise it by 1 GB and test again
• Short freezes every few seconds on a high setting: try lowering it
• Slow loading while other apps compete for memory: close them or reduce the amount

Check your result#

Change one thing at a time. Keep the FPS and Memory elements on your FireClient HUD while you play for ten minutes, then compare. If you are new to the launcher, start with the install guide.

Where the layout is stored#

Positions, visibility and the sprint toggle are saved to config/fireclient/client.json. The path is relative to your Minecraft game folder, so look for a config folder inside it, then fireclient.

Back it up#

1. Close Minecraft so the file is not being written.
2. Copy client.json to a safe place, such as a cloud folder or a USB drive.
3. Put a date in the copy's name, for example client-2026-10-13.json, so you can keep a few versions.

Reuse it on another PC#

Install FireClient on the other PC and run Minecraft 1.21.1 on Fabric once, so the config/fireclient folder exists. Close the game, then put your copy in that folder as client.json. The layout should load the next time you start the game. Keep a copy of the original first in case you want to go back.

When something looks wrong#

If elements end up off screen after a resolution change, open the menu with Right Shift and use Edit HUD Layout to drag them back. The HUD setup guide has the full walkthrough.

Before you share the file#

The file holds layout settings, but open it in a text editor and check it before you post it anywhere. Never post logs or account files publicly. If you are unsure, ask in the FireClient Discord.

Open the menu#

Start a Minecraft 1.21.1 Fabric world and press Right Shift. You can also use the FireClient Menu button on the title screen. The menu has four tabs: Mods, Settings, Keybinds and Mod List.

Switch modules on and off#

The Mods tab shows a card for each module, with an Options button and an Enabled or Disabled switch. Use the filter buttons (All, New, HUD, PvP, Visual, Move and Perf) or the search box to find what you want. The screenshot shows modules such as Target HUD, Crosshair, Hitboxes, CPS, Keystrokes, Armor Items, Item Counts, Hearts, Low HP Alert and Armor Warning.

Turn on only what you read during play. A short list keeps the screen clear, whether you are in a PvP match or building.

See it in a world#

With HUD elements on, the screen can show coordinates, ping, facing direction, memory use, a clock, armor, CPS, hearts and keystrokes, as in this singleplayer world. That is a lot for one screen, so most players keep a handful.

Move things with the HUD editor#

Press Edit HUD Layout in the bottom left of the menu and drag each element where you want it. The HUD: Shown button next to it controls the whole HUD. Positions, visibility and the sprint toggle are saved to config/fireclient/client.json, so your layout is the same the next time you launch.

Save a profile#

The left side of the menu lists profiles such as Default, PvP, Builder and Performance, with a Save Profile button. A simple approach is one profile per situation, for example a minimal layout for PvP and a fuller one for building, and switching between them from the menu.

Keep the layout tidy#

Start with three or four elements and add more only if you miss them. Leave the middle of the screen clear so the HUD never covers what you are aiming at. If elements end up off screen after you change resolution, open the menu with Right Shift and use Edit HUD Layout to drag them back.

If the menu does not open#

The FireClient menu only exists in the in-game client, which is built for Minecraft 1.21.1 on Fabric with Java 21. Check that you launched that version, because the launcher can start other versions but they run without the FireClient mod. You can also use the FireClient Menu button on the title screen. If the game crashes on start, see the Fabric crash checklist, and if Java is the problem, install Java 21.

What you need#

The in-game client is built for Minecraft 1.21.1 on Fabric with Java 21. The launcher can start other versions, but they launch without the FireClient mod.

Next steps#

• Back up and reuse your HUD layout so you never set it up twice
• Best settings for PvP on 1.21.1
• Boost FPS on 1.21.1 with Fabric
• Install FireClient on Windows in five steps

Questions? Ask in the FireClient Discord, or download FireClient to try the HUD yourself.

1. Download the installer#

Get the installer from the Download section. Wait for the file to finish before you open it.

2. Verify the SHA-256 (optional)#

The current beta installer is unsigned, so Windows may show a security prompt. To check that your file is the one we published, compare its hash with the SHA-256 on the download page. In PowerShell:

Get-FileHash .\FireClient-Setup.exe -Algorithm SHA256

3. Run the installer#

Accept the terms and allow the Windows prompt if you trust the source. Read the Terms and Privacy notice first if you have not.

4. Sign in#

Sign in with Microsoft, or use an offline profile.

5. Play 1.21.1 Fabric#

Launch Minecraft 1.21.1 on Fabric to get the in-game menu on Right Shift. The HUD setup guide shows what to do next.

Will an update delete my worlds?#

No. The installer and uninstaller leave your game-data folder in place, including worlds and resource packs. Back up important worlds before you change game files anyway.

Who it is for#

FireClient 1.0 is for players of Minecraft Java Edition on Windows 10 or 11 (64-bit). You need your own Minecraft Java Edition account to play online. It does not run on Bedrock, macOS or Linux.

What is in 1.0#

• The launcher memory setting is passed to Java as the max heap, limited to a safe range.
• The saves library shows each world's own icon, last-saved date and size.
• The resource pack library has no delete action. Packs and worlds stay on disk through updates and uninstall.
• The in-game client has a draggable HUD with eleven elements and three accent themes.

Known issues#

• The installer is unsigned, so Windows may show a security prompt.
• The in-game mod is built for Minecraft 1.21.1 on Fabric only. Other versions launch without it.

Planned#

A crosshair editor and cosmetics are planned but not built yet. They are not part of 1.0. The full version is planned for November 2026, and the early access and roadmap post explains how we will confirm the date.

Before you install#

The installer is unsigned, so read Is FireClient safe? How to check your download first and compare the SHA-256 of your file with the one on the download page when it is shown. Download only from this site or the official GitHub releases page.

After you install#

Open Minecraft 1.21.1 on Fabric and press Right Shift for the in-game menu, then follow the HUD setup guide. Later updates are listed on the news page.

Download FireClient or read the installation guide. Feedback and bug reports are welcome in the Discord.