Tabletop tactics — anywhere.
MSS:84 is a browser-based hex-grid skirmish terminal for BattleTech.
No installs. No login. No dice. Just deploy and play — online or offline.
MSS:84 recreates BattleTech tactical combat on a digital hex map.
Built for tablets, laptops, and desktops, it handles movement, line-of-sight, record sheets, and networked play — while preserving the pen-and-paper feel of BattleTech.
⚡ Fan-built. Professionally engineered. Fully modular.
Connects directly with TRS:80 // Technical Readout System
- Export Lance JSON from TRS:80
- Import into MSS:84 to instantly deploy units with names, pilots, and skills
- Team colors auto-sync (
Alpha,Bravo,Clan,Merc) - Tokens spawn at grid center with record data intact
🛰 TRS:80 + MSS:84 = One Connected Digital Force Pipeline
- Adjustable grid, hex size, and zoom scale
- Paintable terrain, elevation, and cover layers
- New structures layer: buildings, walls, and objectives
- Preset battlefields (valley, city, ridge, crater)
- Label overlays for height, terrain, and cover
- LOS-aware elevation and shadow depth simulation
- Catalog-driven from
/modules/catalog.json - Place, rotate, move, and delete objects with grid snapping
- Real height integration for accurate LOS
- Auto-saved and restored from local state
- Fully included in exported JSON presets
- Adds visual world-building for cities and bases
- Add mechs manually or import from TRS:80 JSON
- Auto-loads pilot info, skills, and team colors
- Rotate (Q/E keys or icons), move, and scale tokens
- Built-in initiative tracker with cycling and highlights
- Toggle Line-of-Sight rays, Fire Arcs, and Range overlays
- Right-click rangefinder between tokens
- Canvas-based rendering for high-speed updates
- Optimized for both desktop hotkeys and touch controls
- Remote play via shared room code
- “Transmit” sends complete battle snapshot
- “Receive” instantly applies synced state with sender label
- Secure Firestore backend, no login needed
- Optional voice or Discord chat recommended
- Local autosave triggers only on placement or move state changes
- Reloads exactly as left — mechs, map, and structures
- Full JSON export/import support
- Board capture as PNG image
- Service Worker caching ensures full offline use
- Dynamic in-app record sheets per mech
- Tracks armor, internals, heat, crits, and ammo
- Pilot skill and effects fully editable
- Persists locally and syncs through network play
(Gunnery / Attacker / Target / Obstacles / Result)
- 2d6 digital hit calculator with auto modifiers
- Handles hit locations, crit checks, and missile cluster rolls
- Works offline, transparent results
- Clean inline panel integration with battle HUD
- Embed Flechs Sheets in left/right panels
- Player-1 / Player-2 dock mode for analog feel
- Optional alternative to integrated sheet
→ https://nevar530.github.io/Battletech-Mobile-Skirmish/
Runs on Chrome, Edge, or Firefox (tablet or desktop preferred).
- Open left panel → Paint terrain and adjust height
- Add cover or buildings
- Load presets or design custom layouts
- Structures snap to grid and respect height modes
- Use right panel → Add manually or import TRS:80 JSON
- Assign pilots, names, and team colors
- Tokens spawn centered with proper facing
- Manage initiative, rotate, or delete as needed
- Move and rotate units
- Toggle LOS and measure ranges
- Open GATOR console for quick hit checks
- Track damage on Mech Sheets
- Sync with Firebase or export for later
- Click Uplink → Join Room
- Enter a shared phrase (e.g.
ember-orbit-fox) - Opponent joins same code
- Press Transmit after each turn
- Field state syncs instantly
| Screenshot | Description |
|---|---|
 |
App Home / Boot Sequence — amber CRT intro screen |
 |
Battle Map — mechs, terrain, and LOS active |
 |
City Map Preset — multi-layer terrain example |
 |
Preset Loader — quick battlefield setup |
 |
Flechs Dock — external sheet integration |
 |
Cross-App — TRS:80 → MSS:84 import pipeline |
📸 Add new screenshots:
images/wiki/structures.png– Structures panel open (rotation + placement)images/wiki/sheet.png– In-app mech sheet with armor/heat visibleimages/wiki/gator.png– GATOR console results panelimages/wiki/sync_banner.png– Firebase sync banner (Transmit confirmation)
| Stack | Description |
|---|---|
| Language | HTML5 / CSS3 / Vanilla JavaScript |
| Rendering | Canvas + SVG multi-layer engine |
| Data | JSON manifests (mechs, structures, presets) |
| Storage | LocalStorage autosave + Firebase Firestore sync |
| Architecture | Modular /modules/ design, self-contained APIs |
| Offline Support | PWA-ready with cached assets |
| Hosting | Static GitHub Pages deployment |
MSS:84 is a fan-made tool for the BattleTech community.
All code © 2025 Nevar530 under the MIT License.
- Mech and weapon data derived from MegaMek (CC-BY-NC-SA).
- No proprietary Catalyst Game Labs assets used.
- Flechs Sheets © BisonAIs (embedded iframe).
BattleTech®, BattleMech®, and related marks are property of The Topps Company, Inc.
Catalyst Game Labs is the current license holder.
This project is unaffiliated with Topps, Catalyst, Microsoft, or MegaMek.
- Lead Dev & Design: Nevar530
- Systems Integration: ChatGPT (OpenAI), under direct instruction
- External Dock: BisonAIs – Flechs Sheets
- Testing & Feedback: Community playtesters & fellow MechCommanders
Inspired by paper maps, coffee-stained record sheets, and thirty years of scorched hexes.
📖 MSS:84 Wiki →
Includes advanced guides, hotkeys, JSON schema, and module documentation.