open.mp

open.mp is a multiplayer mod for Grand Theft Auto: San Andreas that is fully backwards compatible with San Andreas Multiplayer (SA:MP). In practice, that means an existing SA:MP server can move to open.mp without rewriting its scripts or asking players to install a different client: old AMX scripts load directly, and players using the SA:MP client can join an open.mp server.

What "backwards compatible" covers

The compatibility claim on open.mp rests on two separate layers, and both need to work for a server to migrate cleanly.

1. Script compatibility (server side)

open.mp keeps using pawn as its scripting language, and it can load existing compiled SA:MP scripts — the site describes this as loading "an old AMX" straight out of the box. So a gamemode or filterscript compiled for SA:MP does not need to be recompiled or edited before it runs on an open.mp server.

2. Client compatibility (player side)

Players do not need a new client to connect. The site states you can "join your friends playing on the SA:MP client," meaning the existing SA:MP client remains a valid way to play on an open.mp server.

Together these two points are what make a migration possible without touching either the codebase or the player base.

What you can do without changing anything

Where open.mp goes beyond compatibility

Compatibility is the starting point, not the limit. Once a server is running, open.mp offers ways to extend it:

• A new compiler — still for pawn, but engineered to make code more robust.
• More functions — additional functions for manipulating the server and client.
• Documentation — the docs are the intended next step when you want to enhance your code rather than just run it unchanged.
• An extensible C++ API — access to all the server features available in pawn, plus C++ libraries and frameworks, via the SDK repository.
• Open source development — the server is fully open source, and contributions and bug reports are welcomed through the GitHub organization.

Practical migration path

1. Start with what you have. Point your existing AMX script at an open.mp server and confirm it loads and runs.
2. Verify player access. Have someone join using the SA:MP client to confirm the client side works.
3. Only then enhance. When you want new behavior, move to the docs and the improved scripting system rather than changing things up front.

The key takeaway: open.mp is designed so that compatibility is the default state, and modernization is an opt-in step you take afterward.

open.mp is a multiplayer mod for Grand Theft Auto: San Andreas that is fully backwards compatible with San Andreas Multiplayer (SA:MP). Its server is fully open source, and the project welcomes all contributions, big or small. You can contribute by reporting bugs, helping write the next version, or getting involved through the project's GitHub organization. The main entry points are the GitHub organization for general contributions and the SDK repository if you want to work with the C++ API.

Ways to contribute

The project describes community-driven development as a core part of how it operates. Based on the site's own description, contributions can take several forms:

• Report problems. The site states that despite attempts to have perfect code, bugs happen, and user feedback is valuable. If you find an issue, posting about it is a legitimate contribution.
• Help write the next version. The project explicitly invites people to help write the next version of the server.
• Contribute code or fixes. Because the server is fully open source, code contributions of any size are welcome.
• Improve the server through the C++ API. Once you have mastered the extensible C++ API, the site suggests helping improve the server via the open contribution process on GitHub.

Where to start

The site points to a GitHub organization for community contributions and to an SDK repository for the C++ side. If your interest is in scripting, the docs are the place to learn about the improved scripting system before you start changing code.

What you can build on

Understanding the project's technical surface helps you decide where your contribution fits:

• Scripting system. The project kept pawn but introduced a new compiler engineered to make code more robust, along with more functions to manipulate the server and client. If you write or maintain scripts, improvements and fixes in this area are directly relevant.
• Backwards compatibility. Existing scripts and clients remain compatible. An old AMX can be loaded on the open.mp server out of the box, and players can join using the SA:MP client. This means contributions generally do not need to break existing SA:MP scripts to be useful.
• Extensible C++ API. The C++ API exposes all the server features available in pawn, plus the broader universe of C++ libraries and frameworks. This is the path for contributors who want to extend the server itself rather than write scripts.

A practical approach

1. Decide which layer you want to work on: scripts (pawn), the server core, or the C++ API.
2. Read the docs for the scripting system if your contribution touches scripts, so your changes match the current compiler and function set.
3. Go to the GitHub organization, look at open issues, and pick something that matches your skill level — the project states that contributions big or small are welcome.
4. If you are extending server features, check the SDK repository for the C++ API.
5. Submit your change or report through GitHub, following the project's open contribution process.

Common sticking points

• Assuming you need to rewrite everything. Backwards compatibility is a stated feature, so you can often improve or extend without breaking existing SA:MP scripts.
• Skipping the docs. The scripting system uses a new compiler and additional functions; contributing without reading the docs risks working against the current design.
• Thinking contributions must be large. The project explicitly welcomes small contributions, including simply posting about problems you find.

If you are unsure where you fit, start by reporting an issue or reading the docs, then move to code once you understand the area you want to improve.

open.mp keeps Pawn as its scripting language but replaces the compiler and expands the function set, so existing scripts can run while new code gets stronger tooling. The improvements are aimed at two groups: server owners who want to load old AMX files without rewriting them, and scripters who want more control over the server and client. If you only need to run an existing SA:MP gamemode, the backwards compatibility matters most; if you plan to write new code, the compiler and new functions are the relevant changes.

Still Pawn, but a new compiler

The scripting language itself has not changed. open.mp "stuck with pawn," which means existing knowledge, syntax, and most of your code carry over. What changed is the compiler underneath it.

According to the project, the new compiler is "engineered to make your code more robust." In practice that means the toolchain is the improvement target rather than the language. You keep writing Pawn, but the build step is a different, newer piece of software than the one used by the original SA:MP tooling.

What this means for you

• No language migration. You do not need to learn a new syntax or port scripts to another language.
• Rebuild to benefit. Compiler-level improvements apply when you compile your script with the new toolchain, not to an already-compiled AMX.
• Old AMX still loads. A pre-compiled AMX can be loaded on an open.mp server "straight out of the box," so you can defer recompiling until you actually want the new behavior.

More functions for server and client

Beyond the compiler, open.mp adds "more functions to manipulate the server and client." This is the part that changes what your scripts can do, not just how reliably they compile.

The documentation is the place to look for the specific list, since the function surface is what defines the practical difference between scripting on SA:MP and scripting on open.mp. The project points scripters to its docs when they "want to enhance your code."

How to approach the new functions

1. Get a working baseline first. Load an existing AMX and confirm the server runs and clients can join.
2. Then read the docs. The improvements are documented rather than assumed, so the docs are the reference for what is newly available.
3. Adopt incrementally. Because old scripts keep working, you can introduce new functions into a functioning gamemode instead of rewriting it.

Backwards compatibility is the foundation

The scripting improvements sit on top of full backwards compatibility, and that ordering matters. The project states the server is "fully backwards compatible with existing scripts and clients," and describes loading an old AMX and joining "your friends playing on the SA:MP client."

That combination is what makes the scripting changes low-risk to try:

Where the C++ API fits

If Pawn's function set is not enough, open.mp also exposes an "Extensible C++ API" that gives access to "all the server features available in pawn, plus the universe of C++ libraries and frameworks." This is a separate path from the Pawn improvements, but it is worth knowing about if you hit a limit in Pawn.

The trade-off is straightforward: Pawn keeps you compatible with existing scripts and the SA:MP client ecosystem, while C++ opens up external libraries at the cost of leaving the Pawn toolchain behind for that component.

Practical next steps

• Running an existing server: load your AMX on an open.mp server and verify clients connect before changing any code.
• Improving an existing script: recompile with the new compiler, then consult the docs for functions worth adopting.
• Starting fresh: begin in Pawn with the new compiler, and treat the C++ API as an option if you need libraries Pawn cannot reach.
• Contributing: the server is fully open source, and the project welcomes contributions and bug reports through its GitHub organization.

open.mp (Open Multiplayer) is a multiplayer mod for Grand Theft Auto: San Andreas that is fully backwards compatible with San Andreas Multiplayer (SA:MP). If you already run SA:MP scripts or play on SA:MP clients, open.mp is designed to work with them out of the box — you can load an existing AMX script onto an open.mp server and join from the SA:MP client. It is aimed at server owners and scripters who want to keep their existing SA:MP setup while gaining a more actively developed, open-source platform.

Backwards compatibility with SA:MP

The core promise is compatibility, not replacement-with-migration-pain:

• Existing scripts run as-is. An old AMX file can be loaded on an open.mp server "straight out of the box."
• Existing clients connect. Players using the SA:MP client can join an open.mp server.
• Enhancement is optional. You only move to the newer scripting features when you choose to improve your code.

This matters if you maintain a live SA:MP community: you can switch the server side without forcing players to install something new.

What open.mp adds on top

A new scripting system (still Pawn)

open.mp keeps Pawn as the scripting language but ships a new compiler engineered to make code more robust, plus additional functions for manipulating the server and client. So the learning curve for existing SA:MP scripters stays low, while the tooling and API surface improve.

An extensible C++ API

Through the SDK, you get access to all the server features available in Pawn, plus the wider universe of C++ libraries and frameworks. This is the path to take if you want to extend the server beyond what scripting alone allows.

Open-source, community-driven development

The server is fully open source and contributions of any size are welcome. You can help write the next version, or report problems you find — the project acknowledges that bugs happen and treats feedback as valuable.

Who it's for

How to get started

1. Check compatibility first. Confirm your existing AMX script and your players' client setup match what open.mp supports — the project states backwards compatibility with existing scripts and clients.
2. Load your script on an open.mp server. The documented expectation is that an old AMX loads out of the box.
3. Connect with the SA:MP client to verify players can join as before.
4. Then enhance. When you want to improve your code, move on to the docs covering the new scripting system.
5. Go further with C++ if you need server features beyond Pawn, via the SDK repository.
6. Contribute or report issues through the GitHub organization.

The official site (open.mp) links to Getting Started documentation, the SDK repository, and the GitHub organization for contributions.

The Extensible C++ API in open.mp gives you access to every server feature that is available in pawn, plus the wider universe of C++ libraries and frameworks. It is the right choice if you already write C++ or need functionality that pawn cannot easily provide, and you obtain it through the SDK repository on GitHub. If you only script gameplay logic in pawn, you do not need this API at all.

What the C++ API actually gives you

open.mp is a multiplayer mod for Grand Theft Auto: San Andreas that is fully backwards compatible with San Andreas Multiplayer. Its scripting system sticks with pawn, but the server itself is fully open source and exposes an extensible C++ API alongside it.

The key point is parity plus reach:

• Full feature access — you can reach all the server features that are available in pawn.
• Beyond pawn — you can also use the universe of C++ libraries and frameworks, which pawn does not offer.
• Open contribution path — once you have mastered the API, you can help improve the server through the open contribution process on GitHub.

So the API is not a replacement for pawn scripting. It is a second, lower-level way to work with the same server.

When to use it instead of pawn

If your goal is to run or adapt existing SA:MP scripts, pawn is the practical route — an old AMX can be loaded on the open.mp server straight out of the box and played on the SA:MP client. The C++ API becomes relevant when your requirements go past what pawn exposes.

How to get started

1. Go to the SDK repository on GitHub (linked from the open.mp site as the SDK repository).
2. Review the API surface there to confirm it covers the server features you need.
3. Build against it using your existing C++ toolchain and libraries.
4. Once working, consider contributing improvements back through the open contribution process.

The expected result is a component that has the same access to server features as a pawn script, with C++ tooling and libraries available on top.

Common sticking points

• Assuming it replaces pawn. It does not. The scripting system remains pawn, with a new compiler engineered to make code more robust and more functions to manipulate the server and client.
• Skipping the compatibility question. If your existing code is an AMX, you may not need the C++ API at all — test the backwards-compatible path first.
• Treating contribution as optional. The server is fully open source and all contributions, big or small, are welcomed; bugs are expected and feedback is described as valuable.