Tabs in detail

mjEdit organizes work in a multi-tab system. Each tab is specialized for a specific workspace and works seamlessly with the others.

Text Tab — The JSON editor

The heart of mjEdit: a full-fledged JSON editor with syntax highlighting, real-time validation, bracket matching and intelligent auto-repair.

Performance modes for large files

Form Tab — qFORM form system & QC scripts

The Form tab automatically turns JSON data into editable forms. The proprietary qFORM format combines structured data entry with embedded Python scripts (QC scripts) in a RestrictedPython sandbox.

Automatic widget detection

QC script syntax coming soon

QC scripts are embedded in string fields of the qFORM file, compiled into a RestrictedPython sandbox and executed on rendering. The final expression result replaces the code block in the form.

Example 1 — Beginners: Pick-up date for a new passport

An authority qFORM records the day of the application and automatically calculates the earliest collection date (classic: application date + 30 days).

{
  "Reisepass-Antrag": {
    "antragsdatum": "DATUM 06.05.2026",
    "bearbeitungsdauer_tage": 30,
    "abholtermin": "QC: berechneter Termin: @(\nfrom datetime import datetime, timedelta\nantrag = datetime.strptime('<antragsdatum>', '%d.%m.%Y')\nabholung = antrag + timedelta(days=int('<bearbeitungsdauer_tage>'))\nf'{abholung.strftime(\"%A, %d.%m.%Y\")} (frühestens)'\n)@"
  }
}

This is how the QC field is rendered, for example: B. as:

berechneter Termin: Freitag, 05.06.2026 (frühestens)

What’s happening here?

1. <antragsdatum> and <bearbeitungsdauer_tage> are replaced with the current field values before execution.
2. datetime is available in the sandbox, the code calculates Antragstag + 30 Tage.
3. The final expression (f"…") becomes the result - no more boilerplate is necessary.
4. As soon as the clerk changes antragsdatum, mjEdit automatically updates the display.

Example 2 — Advanced: Count SSP implementation status

A pure OSCAL SSP file contains no QC field. However, there is the possibility of evaluating data via a temporary QC field and combining OSCAL files with qFORM in a meaningful way - either directly in the form tab or via an independent qFORM with a file picker (see below):

Variant A — Open SSP directly in the form tab

When you open an OSCAL SSP JSON in mjEdit and view it in the Form tab, the SSP itself is json_data. A QC block temporarily inserted in a free description field can evaluate the entire document - useful for sample statistics during a review:

@(
reqs = json_data.get('system-security-plan', {}).get('control-implementation', {}).get('implemented-requirements', [])
implementiert = sum(
    1 for r in reqs
    for s in r.get('statements', [])
    for bc in s.get('by-components', [])
    if bc.get('implementation-status', {}).get('state') == 'implemented'
)
total = len(reqs)
f"Implementiert: {implementiert} von {total} Anforderungen ({(implementiert/total*100 if total else 0):.1f} %)"
)@

Advantage: No additional tooling, can be used immediately. Disadvantage: The QC block must be removed before saving if the document is to remain schema valid.#### Variant B — Own “SSP statistics” qFORM with file picker

The clean version is an independent qFORM that records a file path to an SSP file and reads it in via urllib. The file path widget (📁 button) is natively supported by qFORM; the QC script accesses the value via <ssp_pfad>:

{
  "SSP-Statistik": {
    "ssp_pfad": "C:/oscal/ssp_acme.json",
    "report": "QC-Bericht: @(\nimport urllib.request, json\nfrom urllib.parse import urljoin\nfrom pathlib import PurePath\nuri = 'file:///' + str(PurePath('<ssp_pfad>')).replace('\\\\','/')\nwith urllib.request.urlopen(uri) as f:\n    ssp = json.load(f)\nreqs = ssp.get('system-security-plan', {}).get('control-implementation', {}).get('implemented-requirements', [])\nimpl = sum(1 for r in reqs for s in r.get('statements', []) for bc in s.get('by-components', []) if bc.get('implementation-status', {}).get('state') == 'implemented')\nf'{impl} von {len(reqs)} Controls implementiert'\n)@"
  }
}

Steps for the user:

1. Open SSP statistics qFORM.
2. Select the SSP file using the 📁 symbol.
3. mjEdit replaces <ssp_pfad> with the selected path and executes the QC script.
4. The result appears live in the form - every path change triggers a recalculation.

Advantage: Reusable, the SSP file itself remains unchanged, the QC script can deliver any complex evaluations (traffic lights per control family, missing components, POA&M references, etc.).

Markdown tab — Documentation and reports

Full-fledged Markdown editor with live preview in split view, GitHub Flavored Markdown, auto-formatting via mdformat and PDF/HTML export.

Advanced task list system

PDF Tab — Viewer, Annotator and Redaction Tool

PDF documents are displayed directly in mjEdit - with multi-tab support, annotations, text search and secure redaction.

• Zoom 25% – 400%, Fit to Width / Fit to Height
• Highlighter, notes, freehand drawing, shapes, text insertion
• Secure redaction with Unicode block (■): Content is actually removed, not just covered over
• Save PDF with all annotations as a new file

Browser tab — Built-in web browser

Full-fledged Chromium-based browser directly in mjEdit - with a two-tier bookmark system.

Global vs. private bookmarks

Save web pages as an OSCAL back matter resource

Any web page displayed can be inserted into an open OSCAL document as a back matter resource by right-clicking - one click instead of copy-pasting between applications.

OSCAL Tabs (Plugin) — Specialized editors

The OSCAL tabs open automatically when mjEdit detects an OSCAL file. A tailor-made editor is available for each of the 8 OSCAL document types - see OSCAL integration.

File Tree View — Central Cockpit

• Lazy loading for large directories (1,000+ files)
• Colored file icons per extension (configurable)
• Real-time filter, case-insensitive and recursive
• Context menu with actions depending on file type
• Backup indicator shows existing backups
• Multi-selection for batch operations
• “Open as text” bypasses automatic OSCAL routing

Backup and versioning concept

mjEdit offers a two-tier safety net:

1. Automatic backups – compressed (GZIP), time-based, on open and save
2. Version Archive - named snapshots with diff display and preview

A backup of the current file is automatically created before each restore.