BOM

BOM is a simple Django app to manage a bill of materials. It supports multiple part numbering schemes, tracking component sourcing information, estimates costs, and contains smart integrations with Mouser to pull in the latest component pricing and Google Drive for part file management. BOM is written in Python 3 and Django.

See a live example.

BOM can be added to an existing (or new) Django project, or stand alone on its own, which can be more convenient if you're interested in tweaking the tool.

If you already have a django project, you can skip to Add Django Bom To Your App, otherwise Start From Scratch: Add to new Django project to add it to a new django project, or Start From Scratch: Use as standalone Django project.

Table of contents

• Start From Scratch: Add to new Django project
• Add Django Bom To Your App
• Start From Scratch: Use as standalone Django project
• Customize Base Template
• Importing and exporting
• Integrations
• MCP Server
• Contributing
• Installation pitfalls

Start From Scratch: Add to a new Django project

1. Create and activate a virtual environment (Python 3.10+):

python -m venv .venv
source .venv/bin/activate   # Windows: .venv\Scripts\activate

2. Install Django and set up your project:

pip install django
django-admin startproject mysite
cd mysite
python manage.py migrate
python manage.py createsuperuser # make a user for your development environment

3. Continue on to Add Django Bom To Your App.

Add Django Bom To Your App

django-bom is a reusable django application. If you don't already have a django project, you can follow some quick steps below to get up and running, or read about creating your first django app here.

pip install django-bom

1. Add "bom" to your INSTALLED_APPS setting like this::

INSTALLED_APPS = [
    ...
    'bom',
    'social_django', # to enable google drive sync in bom
    'djmoney', # for currency
    'djmoney.contrib.exchange', # for currency
    'materializecssform',
]

2. Update your URLconf in your project urls.py like this::

path('bom/', include('bom.urls')),

And don't forget to import include:

from django.conf.urls import include

3. Update your settings.py to add the bom context processor 'bom.context_processors.bom_config', to your TEMPLATES variable, and create a new empty dictionary BOM_CONFIG.

TEMPLATES = [
    {
        ...
        'OPTIONS': {
            'context_processors': [
                ...
                'bom.context_processors.bom_config',
            ],
        },
    },
]

and

BOM_CONFIG = {'standalone_mode': False}

4. Run python manage.py migrate to create the bom models.

5. Start the development server python manage.py runserver and visit http://127.0.0.1:8000/admin/ to manage the bom (you'll need the Admin app enabled).

6. Visit http://127.0.0.1:8000/bom/ to begin.

Start From Scratch: Use as a standalone Django project

1. Clone the repo and create a virtual environment:

git clone https://github.com/mpkasp/django-bom.git
cd django-bom
python -m venv .venv
source .venv/bin/activate   # Windows: .venv\Scripts\activate

2. Install dependencies and start the server:

pip install -e .
cp bom/local_settings.py.example bom/local_settings.py
python manage.py migrate
python manage.py runserver

Customize Base Template

The base template can be customized to your pleasing. Just add the following configuration to your settings.py:

BOM_CONFIG = {
    'base_template': 'base.html',
}

where base.html is your base template.

Importing and exporting

Every export is a valid import: edit a CSV that BOM gave you and upload it on the Import page (/import/). Rows that match existing records update the fields they provide, blank cells leave values alone, and nothing is deleted except BOM lines you replace. Every import is previewed first and saved only when you confirm it.

The Import page detects the type from the file's columns or lets you pick one; /import/?type=parts|prices|bom preselects it, and &parent=<part number> fills in the assembly a BOM import goes into. The former upload-parts/, upload-bom/ and upload-parts-help/ URLs redirect there.

Integrations

Mouser Integration

For part matching, make sure to add your Mouser api key. You can get your key here.

Google Drive Integration

Make sure to add the following to your settings.py:

AUTHENTICATION_BACKENDS = (
    'social_core.backends.google.GoogleOpenId',
    'social_core.backends.google.GoogleOAuth2',
    'social_core.backends.google.GoogleOAuth',
    'django.contrib.auth.backends.ModelBackend',
)

SOCIAL_AUTH_GOOGLE_OAUTH2_SCOPE = ['email', 'profile', 'https://www.googleapis.com/auth/drive', 'https://www.googleapis.com/auth/plus.login']
SOCIAL_AUTH_GOOGLE_OAUTH2_AUTH_EXTRA_ARGUMENTS = {
    'access_type': 'offline',
    'approval_prompt': 'auto'
}

And if you're using https on production add:

SOCIAL_AUTH_REDIRECT_IS_HTTPS = not DEBUG

FIXER

Fixer.io is used to handle exchange rate calculations. This is helpful if you may be purchasing parts from another currency (especially via Mouser) and you still need to estimate your part costs.

To set this up you just need to add your API key to local_settings.py as shown in the example.

To update rates, migrate and run python manage.py update_rates. Some day we will need to add a (celerybeat?) task to update rates on a schedule. Explained more here.

MCP Server

django-bom ships an MCP server so AI clients (Claude Code, Claude Desktop, Cursor, ...) can read and build BOMs in a user's organization. Design notes live in docs/mcp-server-design.md.

Run it standalone with an ASGI server; Django is served alongside it:

uv run uvicorn bom.asgi:application

The server listens at /mcp (Streamable HTTP, stateless). In a host project, mount bom.mcp.asgi.build_mcp_app() and enter bom.mcp.asgi.mcp_lifespan from the host app's lifespan.

Every request needs a bearer token. Create one under Settings > API Tokens (the plaintext is shown once), or issue one for a user from the command line (the plaintext is printed once):

uv run python manage.py create_api_token <username> --name "Claude Code" --scopes read,write

A token acts as that user in their organization: role permissions still apply, and a read-only token can never write. Connect a client with the token in the Authorization header, e.g.:

claude mcp add --transport http indabom http://localhost:8000/mcp --header "Authorization: Bearer <token>"

Hosts can gate access (e.g. by subscription) with BOM_CONFIG['mcp_access_check'], a callable or its dotted path, (organization, user, scopes) -> error message or None, that runs before every write.

Changes and token levels

Every MCP edit is a Change: a bundle of staged items reviewed at /changes/ and applied together (design: docs/changes-design.md). Token scopes set the level: read; read,write can only stage and submit changes for review (propose); read,write,apply can also apply them (create_api_token --scopes read,write,apply). Write tools take an optional change_id to stage into a change from start_change; without it a propose-level token submits a one-item change request and an apply-level token applies it at once. Edits to Released or In Review revisions make the change an Engineering Change Order (ECO): applying it creates a new Draft revision of each edited part (copying its assembly and properties) and a person's approval then releases those revisions, children before parents, and it requires a second person to apply, as do protections in ChangeSettings (including a cost-delta threshold). The review page shows validation, impact (assemblies that use the edited parts) and the unit-cost effect at 100 units, and can rebase a stale change or revert an applied one. Hosts can switch the feature with BOM_CONFIG['changes_review_enabled'], BOM_CONFIG['mcp_apply_enabled'], BOM_CONFIG['eco_enabled'] and BOM_CONFIG['release_approval_enabled'] (callables of the organization or dotted paths; all default on), and set BOM_CONFIG['site_url'] so change URLs returned to MCP clients are absolute.

Admins set the protections (always on for Released and In Review revisions; optionally the primary manufacturer part and a cost-delta threshold, and, when the host enables it, requiring approval to release) in Settings > Organization. With approval required and more than one active member, the Release dialog offers Request approval instead of Release; an Admin may release directly by confirming an override that History records.

After an applied Engineering Change Order, Draft parent assemblies are moved to the new revision automatically and the review page's Cascade panel offers a new Draft revision of each Released parent that still uses the old one.

Editing, Revise, Release and History

Draft revisions are edited directly on the revision's Edit page (description, properties, BOM and manufacturer parts). On a Released or In Review revision the primary button is Revise, which makes the next Draft. Release opens a dialog with the diff against the previous revision, the unit cost before and after and the assemblies that use the part (Draft ones follow automatically, Released ones can be revised with checkboxes), and releases everything in one transaction. Request approval in that dialog opens a change request instead; approving it releases the revisions. A request that releases revisions is an Engineering Change Order. Every direct edit and release is recorded as an unnumbered Change on the part page's History tab and under the History filter at /changes/; the Requests nav item counts open change requests. Compare with... opens a diff of two revisions. Design: docs/editing-design.md.

Contributing

Contributions welcome! Before contributing your work please read the contributing readme.

Also reach out to mike@indabom.com to discuss features, and join our slack channel.

Installation Pitfalls

Windows

Sqlite

You may get an error during your pip install -r requirements.txt related to sqlite. This may be fixed by installing Visual C++ for python...

Cryptography

Sometimes you'll have issues installing cryptography, if this is the case you may just need to set up some environment variables. This stackoverflow may help.