This page covers only what San Andreas Online changes. For standard MTA behavior, use the official MTA Wiki.

San Andreas Online is still experimental. Its capacity patches keep the normal San Andreas defaults unless a server or resource opts into the larger limits.

Start with what you want to build

Goal	Start here	Current scope
Populate the world with synchronized GTA NPCs and traffic	Synchronized NPCs and traffic	Shared civilians, native gang groups, gang combat, motorcycle carjacks, dealers, city cops, civilian couples, and civilian road traffic use GTA’s population, path, and task systems with server ownership and client handoff.
Script San Andreas’ own physics props	Scriptable dynamic objects	GTA-owned dynamic objects appear as client worldobject elements with live transforms plus damage and break events. GTA keeps physics ownership.
Build collision shapes from script	Runtime collision generation	Describe collision as a Lua table of spheres, boxes and meshes instead of shipping a .col, and rebuild it live on models already in the world.
Grow vegetation anywhere	Custom foliage	Hand GTA’s native plant manager a triangle, a surface and a density, and it grows its own grass there with normal rendering and wind.
Control fire as a real element	Managed fire	Server-synchronized fire elements that keep their identity, can be retargeted onto a moving element, and are changed while burning.
Fill the sky with controllable birds	Scriptable birds	Client bird elements with their own renderer, steerable flight, restyling and optional gunshot hit testing, past GTA’s six native ambient slots.
Light the world with GTA’s own effects	Model 2DFX effects	Read, edit, add and remove the 2DFX records baked into GTA models: lights with native blink modes, particles, roadsign text, escalators and sun glare.
Break any object, not just the prepared ones	Object fracture effects	Fragments cut from an object’s live RenderWare geometry at runtime, with durability profiles so ordinary GTA damage triggers the break.
Give an object real physics	Dynamic object physics	Opt an MTA object into GTA’s rigid-body simulation, with position, rotation and both velocities synchronized across clients.
Use GTA’s cranes and winches	Managed ropes	The eight native rope types as synchronized rope elements, with cargo attachment and more logical ropes than the engine has slots.
Load SA-MP / Texture Studio maps	SA-MP maps	Parse Pawn exports directly, resolve SA-MP custom objects, apply material slots, building removals, interiors/worlds, and redistribute the fixed object-streaming budget when needed.
Give the game a PS2-style image or DE radar	SkyGFX, radar, and client visuals	Selected SkyGFX effects, a Definitive Edition radar profile, layout controls, and resource-owned temporary visual overrides.
Read or synchronize GTA radio playback	Native GTA radio playback	Capture and restore the real GTA radio station/track/position/queue state; multiplayer synchronization remains resource-owned.
Discover and join SA:O servers	San Andreas Online client experience	A GTA-style menu combines the public registry with live server data, filters, favorites, artwork, localization, and connection states.
Add verified community identity	SA:O accounts	One server setting enables optional or required San Andreas Online/Discord identity; verified IDs are available before join and in resource bans.
Give custom vehicles their own sound	Custom vehicle audio	Copy an existing Assetto Corsa or Soundize .bank into a resource, assign it to a vehicle, and San Andreas Online makes it follow RPM, throttle and gears automatically. It can also add automatic or Lua-triggered backfire sounds and exhaust flames.
Use more of the world	Extended world	A 20 km XY domain with matching sectors, water, radar, map, pickup, and network work.
Load custom maps through GTA	Native world packs	Give the server a supported static-world pack and GTA loads and streams it as native world content. Format-3 packs can download and load on the first connection without restarting GTA; a set can contain up to eight packs and later be replaced safely at runtime.
Give resources stable custom model IDs	Custom models	Server identities map to local GTA slots with native-parent fallback and cleanup.
Build GTA-style scenes or missions	Story runtime	Native pedestrian pathfinding, driving and combat AI, camera and cutscene leases, mission audio and text, recordings, and actor policies.
See what the mission harnesses prove	Mission checkpoints	Five GTA mission recreations, including complete two-client headless passes for Sweet & Kendl and OG Loc, with exact evidence and remaining visual checks.
Call a specific function	SA:O Lua API	Searchable reference with side, lifecycle, source, commit, native mapping, and test evidence.
Build a gamemode with an AI coding agent	SA:O CLI for AI agents	Give the agent the complete MTA + SA:O API, exact function contracts, project checks, generated context, and real server/client/GTA observations without an MCP server.

World and streaming

Area	Standard MTA:SA	San Andreas Online
Main world-sector grid	120 × 120	400 × 400
LOD world-sector grid	30 × 30	100 × 100
Supported extended-world XY	About −3,000 to +3,000	−10,000 to +9,999
Custom-water grid	12 × 12 / 144 blocks	40 × 40 / 1,600 blocks
Custom-water XY	About −3,000 to +3,000	−10,000 to +9,999
Pickup visual XY	−4,096 to +4,095.875	−10,000 to +9,999
Low-precision network XY	About −8,192 to +8,192	−10,000 to +10,000 on SA:O-capable connections
Absolute network camera range	About −8,192 to +8,192	About −16,384 to +16,384 on SA:O-capable connections
Procedural seabed	Unlimited	Server-configurable 3,000–10,000 or unlimited
Native minimap	Fixed 12 × 12 stock grid	Sparse 40 × 40 logical grid plus Vanilla/Definitive client radar profiles
F11 map	Packaged San Andreas image	Runtime atlas composed from native and registered extended tiles
MTA object streaming split	Fixed 500 normal / 500 low-LOD	Same 1000-slot hard budget, resource-adjustable split including 1000/0
SA-MP map exports	Conversion normally required	Native Texture Studio/Pawn parser, custom-object loader, removals, worlds/interiors, and the SetDynamicObjectMaterial slots a retextured map depends on
Large IMG-backed cities	Basic client IMG links	Bounded resource-managed residency and safe city switching
Native world packs	Not available	Generic format-3 static-world packs loaded through GTA’s own world loader and streaming system, with strict auditing, immutable cache, server isolation, and safe runtime replacement
Reviewed native-world proof packs	Not available	Bullworth, Vice City, Liberty City, and Carcer City; automatic spatial residency with one imported city active at a time

Rendering and native pools

Area	Standard MTA:SA	San Andreas Online
GTA corona pool	64	4,096; 4,094 available to scripted coronas
GTA 3D marker pool	32	4,096
GTA checkpoint pool	32	4,096
Direction arrows	5	4,096
Attribute CULL zones	1,300	4,096
Tunnel CULL zones	40	256
Mirror CULL zones	72	256
Visible entity pointers	1,000	8,192
Visible LOD pointers	1,000	8,192
Streaming RenderWare instances	2,500	30,000
PS2-style post effects	Not built in	Integrated SkyGFX color filter, YCbCr and depth-bias first-run profile; blur and radiosity remain opt-in
Radar renderer	Stock GTA radar	Configurable Vanilla or Definitive Edition profile with widescreen-safe layout controls
Resource visual overrides	No San Andreas Online layer	Allowlisted radar/SkyGFX settings stack by resource and restore player preferences on stop
Native CULL editing	Internal only	Resource-owned Lua CRUD, stable IDs, and cleanup
Project2DFX distant lights	Not integrated	Opt-in static coronas and timed traffic lights from the complete startup IPL catalogue, using a private 25,000-light render queue

Models and gameplay

Area	Standard MTA:SA	San Andreas Online
Custom model identity	Client-local runtime allocation	Server-stable logical IDs mapped to per-client GTA slots
Supported server model types	Not available	Objects, vehicles, and peds with native-parent fallback
SA-MP custom-object identity	Not integrated	Original SA-MP IDs resolved to resource-owned San Andreas Online runtime models by the reference loader
Model-native ped locomotion	No synchronized explicit mode	Shared Lua policy that follows skin changes and recreation
Ambient pedestrian population	Local GTA population remains disabled	Server-owned civilians, native gang groups, dealers, city cops, and civilian couples proposed from GTA’s population and path rules with owner epochs and cleanup
Ambient gang behavior	Local-only single-player logic	Owner-only native groups with leader/follower movement, fight/flee decisions, gang weapons, synchronized damage admission, and bike-jack handoff
Ambient city cops	Local-only, and the retail cop task is unsafe on an MTA ped	A safe ambient-cop wander task on GTA’s verified base locomotion: real path nodes, pauses, and road crossing with wanted, pursuit, and arrest unreachable by construction
Ambient couples	Local-only single-player logic	Atomic two-ped native couple leases with GTA-owned walk side, hand holding, look-at, and give-up distance, plus a separate observer presentation lease
Native dynamic objects	Not exposed to scripts	GTA-owned physics props published as client worldobject elements with live read/write transforms and cancellable damage and break events
Collision authoring	A packaged .col file, fixed at build time	Collision serialized from a Lua table of spheres, boxes and meshes, rebuildable in place on models that are already streamed in
Vegetation placement	Whatever the shipped map contains	Up to 64 resource-owned foliage triangles driving GTA’s native plant manager, with live surface and density changes and dimension support
Fire	Client-only createFire, returning a boolean with no handle	Synchronized fire elements with persistent identity, live strength, duration, damage-mask, spread and target changes, past GTA’s 60-fire pool
Ambient birds	Six native GTA slots, no script access	Resource-owned bird elements with steerable flight, colors, wing beat, render distance and shootability; 128 verified at once
Model 2DFX effects	Baked into models, not exposed	13 client functions to read, edit, add and remove them, with per-resource overrides that roll back on stop
Breakable objects	Only models shipping the DFF breakable plugin	Any streamed object, fractured from its own geometry with no breakable DFF or fracture metadata
Object physics	Objects are static unless scripted frame by frame	Opt-in native GTA rigid-body simulation, with linear and angular velocity synchronized through syncer changes
Ropes	Only the legacy createSWATRope call	All eight native rope types as synchronized elements, with holder tracking, cargo attachment and eight native slots leased across more logical ropes
Native ped story tasks	No direct reusable surface	Reusable movement, driving, combat, dialogue, sequence, and actor-policy primitives
Native AI on non-syncers	Ordinary synchronized element state	Reusable locomotion, rotation, ordered animation, fight/chat, weapon audiovisual, and selected physical/group presentation without competing AI or duplicate damage
Ambient vehicle traffic	Local GTA population remains disabled	Server-owned civilian cars, vans, trucks, motorcycles, BMX bicycles, and quads use GTA’s vehicle choice, road placement, occupants, and DriveWander AI in world 0; boats, aircraft, trailers, parked cars, mission routes, and emergency services remain separate work
Native route continuity	Stream range normally ends native simulation	Resource-owned streaming leases plus a server-owned route harness with owner epochs and syncer reconstruction
Story actor and vehicle policy	General MTA abstractions	Persistent native actor flags, event-profile leases, raw door locks, tyre policy, vehicle proofs, and mission collision loading
Native script camera	Standard MTA camera setters	Resource-exclusive generation-token lease over GTA primitives
Native file cutscenes	Not exposed as a resource-owned API	Stock DAT/CUT/IFP playback with load/start barriers, synchronized skip, fades, completion, and cleanup
Stock entry-exit transitions	Native manager disabled by MTA because its entry path crashes	Optional server-owned Lua runtime using audited IPL pairs, exact on-foot triggers, fades, authoritative interior moves, and rollback
Mission audio	No owned GTA mission slots	Four resource-owned native slots with load recovery and cleanup, plus the original mission-passed tunes
GTA radio playback state	Not exposed to Lua	Client Lua snapshot/restore for station, track, seek position and queue; resources can relay it between clients
Mission GXT text	No resource-owned native lease	Exclusive block lease with small/help/big text queues
Recorded-car playback	Not exposed	Resource-owned direct non-looped native playback
Gang tags	Disabled single-player tag path	Resource-owned native spray hits, persistent 8-alpha progress, Grove rendering, and cleanup
Directional scene load	Not exposed	GTA 0A0B directional preload sequence with finite input validation
Vehicle story gates	Approximate public checks	Exact 09D0 all-wheel predicate and verified vehicle-attached script-audio events
Fast weapon strafe	Not available	Synchronized fastweaponstrafe glitch, disabled by default

The tables describe available code paths, not one shared stability level. Follow the linked system guide for ownership, limitations, and the evidence behind a particular feature.

Tools and tests

• debugscript 4 opens a searchable client/server Lua error inspector with filters, grouped duplicates, capture, and TXT/JSON export.
• The SA:O CLI for AI agents gives coding agents the complete MTA + SA:O API, checks resource metadata and API sides, generates deterministic project context, and can verify that the server, client, and GTA actually joined a test.
• Drag-and-drop DFF/TXD skin and IFP animation previews for local development.
• Extended-world generators, IMG packers, radar extractors, manifest validators, cache tests, and native payload audits.
• A native SA-MP map parser/loader fixture, object-streaming quota harness, native-radio playback resource, and a world-object scripting showcase.
• Focused test resources for engine limits, world systems, native tasks, synchronized population, scene primitives, mission checkpoints, compatibility, and cleanup.
• A CI-built Windows San Andreas Online installer with its own branding, registry state, protocol registration, shortcuts, and uninstall path, isolated from an existing official MTA installation.

See Tooling and verification for the broader test-level definitions. A successful build or static check is not described as an in-game pass.

API inventory

The SA:O Lua API is generated from the final C++ registrations and documents both San Andreas Online additions and existing MTA functions whose side, task, or lifecycle contract San Andreas Online extends. Each entry identifies its actual side, implementation commit, ownership rules, failure conditions, and focused test resource when one exists.