---
title: Offline builder — deep dive & submission
summary: How the single-file HTML builder works under the hood, full feature reference, save/load/import workflow, .json snapshots, what each export tab does, common patterns, and how to submit finished zones to staff for in-game merge.
order: 75
updated: 2026-05-19
---

# Offline builder — deep dive & submission

The [offline builder](/builders/offline-builder) is a **single-file HTML editor** for building JediMUD zones without being connected to the game. Draft your zone offline, export the four canonical files, submit to staff. This doc explains how it actually works + the submission workflow.

## What it is — technically

- One HTML file (`jedimud-builder.html`, ~1700 lines, ~60 KB).
- Embedded CSS + JavaScript — no external resources, no fetch calls, no analytics.
- Runs in any modern browser. Works offline after the first download.
- State persists to `localStorage` automatically on every keystroke (no Save button needed for in-progress work).
- Exports the four canonical zone files plus a portable `.json` snapshot.

The builder doesn't connect to the MUD or to the website. It's a calculator — input boxes in, validated text files out.

## Where state lives

| Surface | Persistence |
|---|---|
| In-memory state | The `state` JS object — lost on tab close |
| Browser localStorage | Auto-saved on every change. Survives reload. Lost on Clear Browsing Data. |
| `.json` snapshot file | Explicit download via "Save .json". Portable across browsers/devices. |
| Four exported files (`.wld/.mob/.obj/.zon`) | Explicit download from the Preview tab. The deliverable to staff. |

The localStorage auto-save uses key `STATE_KEY` (single key, full state blob as JSON). If two tabs are editing in the same browser, the most recent write wins — work in one tab at a time.

## The five tabs

### Zone

Top-level metadata:

| Field | Notes |
|---|---|
| Vnum | Pick a free vnum (ask staff). Defaults to `0`. |
| Name | Display name (`zedit ... Z`). |
| Builders | Space-separated character names — appears in `zone info`. |
| Bot / Top | Vnum range. Auto-computed as `vnum × 100` to `vnum × 100 + 99`. Override if you need a non-standard range. |
| Lifespan min / max | Reset interval range in minutes. Engine picks a random value each cycle. |
| Reset mode | 0=never, 1=when empty, 2=normal. Default: 1. |
| Zone flags | `DESERT`/`WATER`/`OPENLAND`/`MOUNTAIN`/`FOREST`/`CITY`/`ISLAND`/`ARTIC` (terrain) + `WORLDMAP`/`NOBUILD` (behavior). |
| Mort + Imm level range | Soft restrictions — see [Building zones](/builders/zones). |
| Zone history | Free-text changelog field. Use it. |

### Rooms

Each room editor:

- Name (single line, ≤ 60 chars practical)
- Description (multi-line)
- Sector type — drop-down with `inside`/`city`/`field`/`forest`/`hills`/`mountain`/`water_swim`/`water_noswim`/`underwater`/`flying`/`desert`/`cave`
- Room flags — multi-select (`DARK`, `NOMOB`, `INDOORS`, `PEACEFUL`, `SOUNDPROOF`, etc.)
- All 6 cardinal exits + Up/Down (NE/NW/SE/SW available if you toggle diagonal-dir support — depends on tree)
  - Per exit: destination vnum, exit description, door keyword, key vnum, door flags (`ISDOOR`/`CLOSED`/`LOCKED`/`PICKPROOF`/`SECRET`)
- Extra descriptions — keyword-triggered `look at X` text bits

The builder validates that destination vnums **either exist in your zone OR are flagged as cross-zone references**. Cross-zone refs export with the destination as-typed; staff verify at merge time.

### Mobs

Each mob editor:

- Keywords / short-desc / long-desc / detail-desc
- Sex / Position / Default Position
- Level, AC, hitroll, damroll
- HP dice (`NumDice d SizeDice + Add`)
- Bare-hand damage dice
- Gold + XP
- Alignment
- NPC flags (multi-select — `SENTINEL`/`AGGR`/`SCAVENGER`/`STAY_ZONE`/`HELPER`/...)
- AFF flags
- Race / Class / Size (placeholder enums — actual values get resolved at import)

**No spec procs in v1** — you'll attach those in-game via `medit ... P` after the zone merges. See [Building mobiles](/builders/mobiles).

### Objects

Each object editor:

- Keywords / short-desc / long-desc / action-desc
- Item type (drop-down across all 27 types)
- Extra flags + wear flags
- Weight + Cost + Cost/Day + Timer
- Values 0-5 (the builder shows hints about what each val means for the current type — e.g. for WEAPON: val1=dice_count, val2=dice_sides, val3=attack_type)
- Material
- Applies (up to 6 — APPLY_STR/HITROLL/AC/...)

Same as mobs: spec procs come later in-game.

### Resets

The zone reset command list. Per-command:

- Letter — M / O / G / E / P / D / R / A (the standard 8). L/C/K/N/U/J/F/H are placeholders in v1; the cross-zone letters are typically authored in-game where staff can validate cross-zone refs.
- `if` flag — `0`=unconditional, `1`=only if previous succeeded
- Vnums + chance percent + max-in-world

Visual chain-indenting in the UI shows which `G`/`E`/`P` commands belong to which prior `M`/`O`.

### Preview

Four read-only views of the exported files. Each has:

- **Copy** — to clipboard
- **Download** — as `.<type>` file with the right extension

Plus a single **"Export zone"** button that downloads all four at once.

## Save / load / import

### Save .json — the portable snapshot

Click "Save .json" in the toolbar. You get `<zone-name>.json` — a full state blob you can:

- Email to yourself
- Sync to Dropbox / a USB stick
- Open in another browser via "Load .json"
- Carry between devices

This is the **work-in-progress** format. Don't submit this to staff — they want the four canonical files instead.

### Load .json

Open a `.json` snapshot — replaces current state. Confirms first.

### Import zone files

If staff have given you the existing source files of a zone you want to **extend**, click "Import zone files" and select one or more of `.wld/.mob/.obj/.zon`. The builder parses them back into editable state.

Use cases:

- Extending an existing zone (download from staff, import, add rooms, re-export, resubmit).
- Templating off a similar zone (import for the layout pattern, then modify).
- Rescuing pre-OLC zone files from old MUDs (round-trip through the builder to clean up format).

The parser is forgiving but not perfect — exotic non-standard zone-file formats might lose some details. Always preview after import to confirm the round-trip preserved your data.

## Validation

The builder warns inline on common mistakes:

- Vnum out of range — your zone is 30 (3000-3099), you put a room at vnum 4000.
- Exit dest doesn't exist in this zone — flagged as a cross-zone ref (you confirm or fix).
- Reset command references missing entity — e.g. `M 0 3000 1 9999 100` (room 9999 doesn't exist in your zone).
- Missing required fields — keywords on a mob, a room name, a sector type.
- Sector + room flags mismatch — `INDOORS` on a `water_swim` room is suspicious.

Validation is **non-blocking** — you can export with warnings, but staff will flag them on submission.

## Common patterns

### Three-room mini-zone with one mob

A useful smallest-example. Three connected rooms, one wandering mob with a couple grants.

1. **Zone** — vnum 80, range 8000-8099, lifespan 20-30 min.
2. **Rooms** — 8001 (entrance), 8002 (middle), 8003 (deep). 8001's `north` → 8002; 8002's `north` → 8003. 8001's `south` → -1 (an exit to the outside world; staff will wire it post-merge).
3. **Mob** — 8001, a wandering troll. Lvl 5, no AGGR, `STAY_ZONE` flag.
4. **Object** — 8050, a club. WEAPON, `2d4+1`, drops from the troll.
5. **Resets**:
   - `M 0 8001 1 8002 100` (troll into middle room)
   - `G 1 8050 1 100` (give club to troll, if-flag=1)
6. Export, submit.

### Forest with a wandering encounter table

1. Zone: 90, range 9000-9099, FOREST flag.
2. Build ~20 rooms in a connected forest layout.
3. Build 4-5 different mob vnums (wolf, bear, deer, traveler, etc.).
4. Reset commands: `M 0 9001 N <room> <chance>` for each mob, with **chance 25-50** (instead of 100) — the lower chance produces a varied encounter table on each reset.
5. Use STAY_ZONE on aggressive mobs so the wolf doesn't wander into town.

### Indoor dungeon with a boss

1. Zone: 100, range 10000-10099, no terrain flag (it's a dungeon — INDOORS).
2. Boss room at 10050. INDOORS, NOMOB (so adds don't wander out), maybe DARK.
3. Boss mob — high level, MULTHIT0 or MULTHIT1, MEMORY, AGGR. No STAY_ZONE (boss stays put because the room is NOMOB-flagged).
4. Boss object — e.g. a unique sword. Reset with **chance 100** so it always loads when the boss does.
5. Death drop comes from a spec proc attached in-game after merge.

## Submission to staff

When the zone is ready:

1. **Pre-flight check**:
   - Every room reachable from the zone's entry point.
   - No vnum collisions with other zones (ask staff or check the [Zones browser](/builders/zones/) tool).
   - All reset commands reference vnums that exist in your zone or are confirmed cross-zone.
   - Zone history field has your name + date.

2. **Export**: Preview tab → "Export zone" → download all four files.

3. **Naming**: rename to match the zone's vnum:
   - `30.wld`, `30.mob`, `30.obj`, `30.zon` if your zone vnum is 30
   - Match the **zone vnum**, not the bot-vnum of the range. (Zone 30 has rooms 3000-3099, but the files are `30.*` not `3000.*`.)

4. **Submit**:
   - **Discord**: drop into the `#zone-submissions` channel (or whatever your tree uses) with a short summary.
   - **Email**: to `jedi-admin@jedimud.net` with the four files attached + a description of what the zone is.
   - **In-game**: tell a staff member you have a zone ready; they may want to see it before you send.

5. **Review feedback** — staff will reply with merge status. Common feedback:
   - Vnum reassigned (your originally-picked vnum was already taken).
   - Stats out of band (a level-5 mob with 500 HP — staff will ask you to scale).
   - Missing extra descriptions on key rooms.
   - Reset command sequence has a bug.

6. **Iterate** — fix and resubmit.

7. **Post-merge OLC** — once your zone is in-game, you'll get access to `zedit` on it (your name in the builders list grants that). Refine via `zedit/redit/medit/oedit` going forward. The offline builder is for greenfield work + bulk edits; in-game OLC is for tuning.

See [Zone import process](/staff/docs/zone-import/) for what staff does on the receiving end.

## Limitations

The offline builder doesn't currently handle:

- **Shops** (`.shp`) — author in-game via `sedit` after merge.
- **DG triggers** (`.trg`) — author via `trigedit` (or hand-write the file and submit alongside).
- **Quests** (`.qst`) — `qedit`.
- **Spec procs** — attach via the `P` menu in `medit`/`oedit`/`redit` after merge.
- **Cross-zone reset commands** (L/C/K/N/U/J/F/H) — author in-game where staff can validate the cross-zone refs.
- **Per-room motion text** (the passive ambient lines) — author via `redit ... M`.
- **Extra fields**: vnum ranges may differ on alpha vs dev vs prod — your zone might import slightly differently. Coordinate with staff if you're targeting a specific tree.

V2 will close these gaps. For now: do the bulk of the work offline, then refine in-game.

## Privacy

The builder is **fully client-side**:

- No network requests of any kind.
- No analytics, no cookies, no telemetry.
- Your project state is in your browser's localStorage + the `.json` files you download.
- Closing the tab doesn't delete state, but clearing browser data does — back up to `.json` regularly.

You can verify this by opening the file in a text editor — every `fetch`, `XMLHttpRequest`, or external `src=` is auditable. There are none.

## Tips

- **Save .json before every export.** If the export step crashes the browser (large zones can be slow), you don't want to lose your work.
- **Use git for the .json snapshots.** A private repo of your `.json` snapshots gives you version history for your draft work.
- **Reset chance < 100 is normal.** Even staff-built zones use 25-75% chance on many mobs for variety.
- **Don't over-flag.** AGGR + STAY_ZONE + MEMORY + HELPER on every mob makes the zone unplayable.
- **Match your zone's terrain.** If FOREST flag is set, the rooms should be `forest` sector type or the weather feels disjoint.

## Related

- [Offline builder landing page](/builders/offline-builder) — download + quick reference.
- [Building zones](/builders/zones) — zedit details for post-merge refinement.
- [Building rooms](/builders/rooms), [Building mobiles](/builders/mobiles), [Building objects](/builders/objects) — what each editor offers in-game.
- [Zone import process (staff)](/staff/docs/zone-import/) — the receiving end of submission.
- [Building triggers](/builders/triggers) — for the DG scripts you'll add post-merge.