Companion app for X4: Foundations. A Windows desktop app built with Tauri 2 + React + Rust.
Tested on v8 saves (vanilla + all DLCs), not tested on V9 yet.
Unofficial tool, not affiliated with Egosoft. Use at your own risk.
Current release: v1.37.0
- NEW (Fitting tool): Mod support - select mods per slot directly in the fitting tool
- Global mods: one Ship mod, one Engine mod, one Shield mod per fitting
- Per-slot mods: one mod per individual Weapon / Turret slot
- Mods are stored in the custom fitting XML and injected into saves with max-value stats
- ModPicker panel: searchable list filtered by category, Mk quality badges, min–max range display
- NEW: Refit (Fleet tab): Open the fitting tool directly from any fleet ship
- Each ship now has a Refit button - loads its current loadout and mods from the save
- Refit changes are queued and flushed in a single streaming pass on Apply (no extra write per ship)
- Ships with a pending refit are highlighted with a filled button and a “Refit ●” label
- NEW: Mod write-back: Full mod support in the Refit workflow
- Global mods: Ship / Engine / Shield mods applied at the ship root level
- Per-slot mods: one mod per Weapon / Turret slot, injected with max-value stats
- Improvement: Sortable columns in the Fleet and Employees tabs
- Improvement: Load a custom fitting directly in the Ship Comparator without having to select a ship first
- Improvement: Research tab now defaults to tree view
- Improvement: Fitting tool and Ship Comparator ship lists now show resolved names for faction and ship type (e.g. "Heavy Fighter" instead of "heavyfighter")
- Improvement: Fitting tool and Ship Comparator ship lists filtered to hand-validated ships only (ships with a template confirmed fittable in-game) — excludes Kha'ak, unfittable Xenon hulls, and other NPC-only entries
Current release: v1.36.0
- NEW: The player can now add ALL missing items to his own inventory in one click
- NEW: The player can now set a global quantity for all items in his inventory in one click
Current release: v1.35.0 - Major internal refactoring - architecture, stability, and correctness
This release is a structural overhaul driven by a full code audit. No new user-facing features, but the codebase is significantly more solid.
- Architecture: Rust backend split from one 3 400-line monolith into 5 focused modules (types, parser, writer, station, catalog)
- Architecture: TypeScript types now auto-generated from Rust structs via ts-rs — eliminates silent type-mismatch bugs between Rust and frontend
- Architecture: Rust test suite added covering save parsing and write round-trips
- Architecture: Catalog data fully migrated from SQLite to JSON (final migration: mod stats)
- Architecture: Ships and equipment catalog lazy-loaded on first use instead of unconditionally at startup
- Architecture: Catalog read cache — disk reads happen once per session regardless of how many views request the data
- Dictionaries: XS-size ships, weapons, and engines excluded from all catalog browsers (NPC-only items not relevant to the player)
Current release: v1.34.0
- New: Research module added to the player save (table mode and flow mode)
- New: Research entries are hierarchically linked, following the game's prerequisite chain
- New: Players can now unlock research technologies and inject them into their save
Current release: v1.33.0
- Fix: correction of the backup system where a saved save could be overwritten when applying changes
- Fix: automatic cleaning of .tmp files in case of write error
- Fix: save_path() validated on all tauri commands
Current release: v1.32.0
- New: desktop icon for the application
- New: the mods tab now shows components, quantities and research level needed to produce a mod
- New: the player inventory tab now lets you inject needed components and quantities needed to produce a mod
Current release: v1.31.0 (development history starts here, earlier commits live in a private and very messy repo.)
Five top-level views, accessible from the toolbar. No save file required for Dictionaries, Map, Fitting, and Ship Comparison:
| View | Description |
|---|---|
| Editor | Load a save file and browse/edit its contents across 13 tabs |
| Dictionaries | Browsable catalog of all in-game ships and equipment |
| Map | Full interactive universe map with faction control and overlays |
| Fitting | Design ship loadouts with live stat calculations |
| Compare | Side-by-side multi-ship comparison (max 4). Choose your reference ship using the radio button |
Partly out of necessity. X4 existing tools cover some ground, but never quite the way I wanted. Partly out of curiosity and personal challenge: making sense of the save file XML structure, reverse-engineering the game's stat formulas, and figuring out how a long-time Delphi developer could build something modern and cross-platform without losing his mind in the process.
X4 also scratches a very specific itch. After ten years of EVE Online, I needed something almost as deep, but less demanding on online time. X4 delivers. And like any good EVE player, I eventually had to build a spreadsheet. This one just happens to have a UI.
Standing on the shoulders of giants: this project wouldn't have gotten off the ground without the following resources and open source work. Among the dozens I have read:
- Mistralys/x4-savegame-parser: the first thing I dug into to understand the save file structure
- TuxInvader/X4-Info-Miner: invaluable for understanding what data was actually worth extracting
- BeamerMiasma/X4-Foundations: savegame analysis and visualization, another great reference
- X Community Wiki: the authoritative reference for game mechanics
- enenra/x4modding - Universe Creation: essential for making sense of the galaxy map XML
- Quantum Anomaly: inspiration for the fitting tool approach (and old EVE memories)
- Roguey's X4 site: a goldmine of ship and equipment data
Open any .xml or .xml.gz save file and browse 13 tabs:
| Tab | Access | Description |
|---|---|---|
| Overview | R/W | Player name, money |
| Map | R | Save-centric player map: Only visited sectors, true faction ownership, gates, NPC stations, ship-presence highlight |
| Inventory | R/W | All wares with editable quantities, grouped by categories |
| Blueprints | R/W | Full blueprint list (12 categories): Filter Owned / Missing / All, select/deselect all per category |
| Research | R/W | Full research tree (and table): unlock research |
| Reputations | R/W | All 33 factions: colored rank badges, slider editor (capped at ceremony thresholds), licences display |
| Fleet | R/W | All player ships: hierarchical fleet formations, nested sub-fleets, expandable loadout (shields, weapons, turrets, engines, equipped mods in orange), editable ship names, cross-navigation to Employees/Stations. Refit button on every ship (including fleet members): opens the fitting tool pre-loaded with the ship's current loadout, queues changes and flushes in a single pass on Apply |
| Employees | R/W | All NPCs: 5 skills, star rating (0–15), editable per-trait (quick actions All 5 / All 0), linked ship or station. Sortable columns |
| Stations | R/W | Player stations: modules, manager, cargo with editable amounts |
| Deployables | R | Active drones, satellites, and beacons by sector |
| Stats | R | In-game player statistics |
| Messages | R | Player inbox |
| Inject | R/W | Inject ship templates or saved custom fittings directly into the save |
- S / M / L / XL templates: ~300 pre-extracted ship templates organized by size class, with preview images
- Custom fitting injection: inject any fitting saved from the Fitting tool — mods are applied automatically
- Smart placement: injected ships appear around the player's current position, collision-free (3-layer radial algorithm)
- Correct zone targeting: uses
lastcontrolledto find the actual piloted ship - Clean crew: named NPC pilot removed from cockpit, anonymous crew preserved and promotable in-game
- Batch injection: queue multiple ships, inject in one click
Browsable reference for (almost) all in-game equipment and ships, generated from the game's own XML files:
| Tab | Content |
|---|---|
| Ships | All ships: size, type, faction, hull, cargo, slots breakdown, physics, price |
| Weapons | Fixed weapons: DPS, range, damage, reload |
| Turrets | Turret weapons: same stats |
| Engines | Engines: forward/reverse/travel thrust, boost |
| Shields | Shield generators: capacity, recharge rate and delay |
| Thrusters | Thrusters: strafe, pitch, yaw, roll thrust |
| Equipment Mods | All equipment mods: category, quality tier, stat multipliers |
Full X4 universe map accessible from the toolbar (no save required):
- Faction coloring: hexagons colored by controlling faction
- DLC filters: toggle Base / Terran / Split / Pirate / Boron / Timelines / Packs
- Zoom & pan: smooth navigation
- Sector labels: scale-aware, rendered in SVG
- Gates: positions from game XML, visual connections between gate pairs (no highways for now)
- NPC stations: 204 fixed stations (shipyards, wharfs, equipment docks, trade stations, defense stations, pirate bases), filterable by type and DLC
- Tooltips: cluster and sector info (resources, description, faction logo); station type on hover
- Light/dark theme
The Map tab inside the Editor is a separate save-centric view: only visited sectors are revealed, with fog on unexplored space and a player ship highlight.
Design and simulate ship loadouts with live stat calculations:
- 4-column layout: ship selector, individual slot assignment, compatible equipment picker, live stats always visible
- Ship filters: by size class (S / M / L / XL), faction, type — filtered to ships confirmed fittable in-game, with resolved names (e.g. "Heavy Fighter", "Argon")
- Slot groups: Weapons / Turrets / Hull Shields / Section Shields / Engines / Thruster, with count by size
- Live stats: total shields, max speed, travel speed, boost speed, maneuverability, DPS, docking capacity, hangar storage (calculation formulas still WIP)
- Module substitution: swap any slot and see the diff vs baseline in green/red
- Mod support: global mods (Ship / Engine / Shield) + one mod per Weapon / Turret slot; injected at max-value stats
- Save / load fittings: named custom fittings stored in
AppData/Roaming/X4 Companion/custom_fittings/; mods included - Inject into save: send a saved fitting directly to the Inject tab — mods are applied automatically
Side-by-side comparison of multiple ships across all catalog stats (hull, cargo, speed, slots, physics). Ships filtered to the same hand-validated set as the Fitting tool. Load a saved custom fitting directly without pre-selecting a ship.
Download the latest installer from the Releases page:
X4Companion_1.37.0_x64-setup.exe— NSIS installer (recommended)X4Companion_1.37.0_x64_en-US.msi— MSI package
No dependencies required. Windows 10/11 with WebView2 (included by default since Windows 11).
- Launch X4 Companion
- Click the gear icon to set your X4 saves folder
- Click Open save file and select a save (
.xmlor.xml.gz) - Click the Load button and wait for your save to be read
- Browse the tabs and edit what you need
- Click Apply changes once you are satisfied (no need to apply between tab changes). A
.bakbackup file is created automatically before writing.
NOTE: Only one
.bakfile will be created, containing the original save file. Any further changes on the same save will be written directly to the already modified save, preserving the original.
Do not edit a save while X4 is running.
Well you can… you’ll have to reload the save anyway :D
- Open a save file
- Go to the Inject tab
- Select ships from the S / M / L / XL dropdowns, or pick a saved custom fitting
- Click Inject (N): ships appear around the player's position in-game with no AI pilot, you’ll need to promote one of the crew members or teleport to the ship
Available from the main toolbar without opening a save file.
| Operation | Time (520 MB uncompressed save) |
|---|---|
Open .xml or .gz |
~2-3 seconds |
Apply + write .gz |
~5–30 seconds depending on the number of edits and injections |
Streaming parser, no full DOM load at any point. The write bottleneck is gzip recompression.
Requirements: Node.js 18+, Rust stable, Tauri CLI v2
git clone https://github.com/dirlligafu/X4Companion.git
cd X4Companion
npm install
# Dev (hot-reload)
npm run tauri dev
# Production build
npm run tauri buildStack: Tauri 2 · React 18 · TypeScript · Rust · shadcn/ui · Tailwind CSS v4 · Lucide icons
Distributed without warranty of any kind. X4: Foundations is a trademark of Egosoft.