Powerbi Modifying Theme JSON

Power BI Report Themes

Why Themes Matter

A report without a well-designed theme accumulates formatting debt. Every visual ends up with its own bespoke title size, shadow toggle, border style, and hardcoded colors in visual.json. This creates three problems:

1. Inconsistency. Visuals drift apart as authors format each one individually. One card has 14pt titles, another has 12pt; one chart has shadows, another doesn't. The report looks unfinished.
2. Fragility. Rebranding or updating the visual style means touching every visual.json individually. A report with 40 visuals across 8 pages means 40 files to edit. With a theme, it's one file.
3. Bloated visual JSON. Each bespoke override adds lines to visual.json, making reports harder to diff, review, and maintain. A clean visual.json should contain field bindings, position, and conditional formatting; everything else should come from the theme.

Reports using the default Power BI theme or a minimal custom theme (just dataColors and a name) are leaving most formatting to Power BI's built-in defaults, which change between Desktop releases. A well-designed theme locks in the intended appearance.

Signs a theme needs attention:

• Many visuals have objects or visualContainerObjects with redundant formatting
• Visuals of the same type look inconsistent (different title fonts, shadows on some but not others)
• The theme JSON has few or no visualStyles entries
• The report uses a built-in theme like "Default" or "Classic" without customization

Tooling preference: Use pbir CLI when available (pbir theme colors, pbir visuals clear-formatting). Fall back to direct jq modification when unavailable. Always validate after every write.

Tip: Theme JSON files can be 75KB+ and 2000+ lines. Do not read the full monolithic file. Use pbir theme serialize to split into small editable files (see Author/Modify workflow below), or use jq to extract only specific keys. Serialized fragments from the serialize/build workflow are small and safe to read directly.

For PBIR JSON mechanics (property names, filter pane selectors, ThemeDataColor syntax, jq patterns), see the pbir-format skill (pbip plugin) -> references/theme.md.

The Formatting Hierarchy

Power BI applies visual formatting through a four-level cascade. Each level overrides the level above it:

Level 1  Power BI built-in defaults
         |
Level 2  Theme wildcard     visualStyles["*"]["*"]           applies to ALL visuals
         |
Level 3  Theme visual-type  visualStyles["lineChart"]["*"]   overrides wildcard for that type
         |
Level 4  Visual instance    visual.json objects +            overrides everything
                            visualContainerObjects

Core Principle

Push as much formatting as possible into levels 2 and 3. A well-designed theme means:

• Visual JSON files stay lean — no bespoke formatting noise cluttering visual.json
• Global style changes require editing one file
• New visuals automatically inherit correct defaults without manual intervention

Visual-level overrides (level 4) should exist only for true one-offs: content-specific formatting, exceptions to the visual-type default, or conditional formatting expressions.

Diagnosing Why a Visual Looks the Way It Does

When a visual renders unexpectedly, walk up the cascade:

1. Check visual.json → objects and visualContainerObjects (level 4 always wins)
2. Check theme visualStyles["<type>"]["*"] for that visual type (level 3)
3. Check theme visualStyles["*"]["*"] wildcard (level 2)
4. If absent everywhere, Power BI is applying a built-in default

Workflow: Audit Theme Compliance

Use when assessing whether a report's visuals are inheriting from the theme or have accumulated stale overrides.

Step 1 — Locate the custom theme:

THEME_NAME=$(jq -r '.themeCollection.customTheme.name' Report.Report/definition/report.json)
THEME="Report.Report/StaticResources/RegisteredResources/$THEME_NAME"

Step 2 — Review what the theme sets at wildcard level:

# Preferred
pbir theme colors "Report.Report"
pbir theme text-classes "Report.Report"

# Fallback
jq '.visualStyles["*"]["*"] | keys' "$THEME"

Step 3 — Continue with full audit process — see references/theme-compliance.md for the complete workflow: scanning all visuals for bespoke overrides, classifying stale vs intentional vs CF, severity levels, and fix decision tree.

Workflow: Enforce Theme (Clear Overrides)

After applying a new theme or making significant theme changes, stale visual-level overrides prevent the new theme from rendering correctly.

With pbir CLI (preferred):

# Clears bespoke formatting while preserving conditional formatting expressions
pbir visuals clear-formatting "Report.Report/**/*.Visual" --keep-cf -f

With jq (manual, per-visual):

# Safe: clear container chrome only (title, border, background, shadow, padding)
# Does NOT touch chart-specific objects or conditional formatting
jq 'del(.visual.visualContainerObjects)' visual.json > tmp && mv tmp visual.json

# Aggressive: clear everything including chart-specific overrides
# WARNING: also removes conditional formatting — only use if CF is confirmed absent
jq 'del(.visual.objects) | del(.visual.visualContainerObjects)' visual.json > tmp && mv tmp visual.json

# Always validate after
jq empty visual.json

When in doubt, clear visualContainerObjects only. Leave objects unless you have confirmed no conditional formatting exists in that visual.

Workflow: Author or Modify a Theme

When building or substantially revising a theme, use the serialize/build workflow via pbir CLI. This splits the monolithic theme JSON into small, focused files that are easy to read and edit without loading 2000+ lines of JSON into context.

Serialize/Build Workflow (Recommended)

IMPORTANT: Serialize to a temporary folder outside the .Report/ directory. The PBIR validation hooks monitor .Report/ for JSON changes and will flag the serialized fragments as invalid PBIR files. Use /tmp/, a sibling folder, or the -o flag to place the .Theme folder elsewhere.

Step 1 — Serialize the theme into editable files:

# From a report (outputs to a .Theme folder)
pbir theme serialize "Report.Report" -o /tmp/MyTheme.Theme

# From a standalone theme JSON file
pbir theme serialize theme.json -o /tmp/MyTheme.Theme

This produces small, focused files: _config.json (colors, text classes, named colors), _wildcards.json (wildcard visual styles), and one file per visual-type override (e.g., slicer.json, page.json).

Step 2 — Edit the serialized files. Each file is small enough to read and edit directly. Focus on:

1. _config.json — dataColors, semantic colors, textClasses, background/foreground variants
2. _wildcards.json — container defaults (title, border, shadow, padding)
3. Visual-type files — overrides for specific types (textbox, image, card, etc.)

Step 3 — Build and apply back to the report:

# Build only (produces a merged theme.json)
pbir theme build /tmp/MyTheme.Theme

# Build and apply directly to the report
pbir theme build /tmp/MyTheme.Theme -o "Report.Report" -f --clean

The --clean flag removes the .Theme folder after building.

Quick Modifications (No Serialize Needed)

For small, targeted changes, use the CLI directly without serializing:

pbir theme set-colors "Report.Report" --good "#00B050" --bad "#FF0000"
pbir theme set-text-classes "Report.Report" title --font-size 14 --font-face "Segoe UI Semibold"
pbir theme set-formatting "Report.Report" "*.*.dropShadow.show" --value false

See the pbir-cli skill → references/modifying-theme.md for full CLI command reference.

Design Sequence

Whether using serialize/build or direct CLI commands, follow this order:

1. Start from a valid base. Use a template (pbir theme apply-template), the SQLBI/Data Goblins theme, or a community template. Do not author from an empty {}.
2. Design the color system first (dataColors, semantic colors, background/foreground variants). Color decisions cascade everywhere.
3. Set typography (textClasses) — font face and size for title, header, label, callout, dataTitle. Stick to Segoe UI / Segoe UI Semibold; custom fonts will not render on other users' machines.
4. Set wildcard container defaults (visualStyles["*"]["*"]): title visibility/font/size, dropShadow.show: false, padding, border, filter pane.
5. Add visual-type overrides for types that differ from the wildcard — at minimum, textbox and image to suppress title/border/background/shadow.
6. Validate with pbir theme validate "Report.Report", deploy, and visually verify.

For detailed design guidance, see references/theme-authoring.md. For visual-type override patterns, see references/visual-type-overrides.md.

Workflow: Promote Bespoke Formatting to Theme

When a visual.json has formatting that should become a theme default — either for that visual type or for all visuals — promote it.

With pbir CLI (preferred):

# Preview what would be pushed from a well-formatted visual into the theme
pbir theme push-visual "Report.Report/Page.Page/Card.Visual" --dry-run

# Push formatting to theme as the default for that visual type
pbir theme push-visual "Report.Report/Page.Page/Card.Visual"

# Push only specific components (title, background, border, etc.)
pbir theme push-visual "Report.Report/Page.Page/Card.Visual" --components title,background,border

Manual process (when CLI is unavailable):

1. Identify what's in visual.objects (chart-specific) and visual.visualContainerObjects (container chrome)
2. Decide whether it belongs in the wildcard (["*"]["*"]) or a visual-type section (["lineChart"]["*"])
3. Write the value into the theme, then validate
4. Remove the override from the visual, then validate
5. Verify the visual still renders correctly

Both objects and visualContainerObjects properties map to the same visualStyles[type][state] section in the theme. The distinction in visual.json doesn't exist in the theme.

For complete property mapping tables, wildcard vs visual-type decision guide, color handling, and batch promotion across many visuals, see references/promoting-formatting.md.

Workflow: Validate a Theme

With pbir CLI (preferred):

# Validate a report's theme (checks JSON syntax, structure, and completeness)
pbir theme validate "Report.Report"

# Validate a standalone theme file
pbir theme validate "theme.json"

# Validate a serialized .Theme folder before building
pbir theme validate "MyTheme.Theme"

Manual validation (when CLI is unavailable):

# 1. JSON syntax
jq empty "$THEME" && echo "JSON valid"

# 2. Required top-level keys
jq '{dataColors: (.dataColors | type), visualStyles: (.visualStyles | type), textClasses: (.textClasses | type)}' "$THEME"

# 3. Wildcard section
jq 'if .visualStyles["*"]["*"] then "wildcard exists" else "MISSING wildcard" end' "$THEME"

# 4. Valid hex colors
jq '[.dataColors[] | select(test("^#[0-9A-Fa-f]{6}$") | not)]' "$THEME"

# 5. No null visual-type sections
jq '[.visualStyles | to_entries[] | select(.value == null) | .key]' "$THEME"

After validation, deploy and visually verify:

• Wildcard container chrome (titles, borders, shadows) applies to all visuals
• Filter pane and filter cards render correctly on all pages
• Visual-type overrides correctly suppress the wildcard for exempt types (e.g., textboxes have no title)
• Data colors cycle correctly on multi-series charts

Schema and Documentation

IDE Integration ($schema)

Add a $schema property to the theme JSON to enable autocomplete and validation in VS Code (or any JSON Schema-aware editor):

{
  "$schema": "https://raw.githubusercontent.com/microsoft/powerbi-desktop-samples/main/Report%20Theme%20JSON%20Schema/reportThemeSchema-2.152.json",
  "name": "MyTheme",
  "dataColors": ["#1971c2", ...]
}

The schema is used verbatim by Power BI Desktop to validate themes on import — if the JSON fails schema validation, Power BI Desktop will reject the theme. Always target the schema version that matches the Power BI Desktop version in use. Schemas follow the pattern reportThemeSchema-2.{version}.json where the version matches the monthly Desktop release.

Theme Top-Level Keys

Invalid Properties to Avoid

These properties look plausible but are not in PBI's theme schema. Including them causes PBI Desktop to fail silently or crash when loading the report:

Safe top-level keys for a custom theme: name, dataColors, background, foreground, tableAccent, visualStyles, textClasses, outspaceColor, borderColor, shapeColors

Always use pbir theme diff to preview changes before applying, and open the report in Desktop once to confirm it loads before committing the file.

References

• references/theme-authoring.md — Color system design, typography, wildcard minimum set, schema integration
• references/serialize-build.md — Serialize/build workflow: splitting themes into editable files, editing, rebuilding, validation, temporary folder guidance
• references/applying-themes.md — Applying templates, post-apply enforcement, clearing visual overrides, normalizing hardcoded colors
• references/copying-themes.md — Copying themes between reports, extracting/downloading themes, comparing themes, consolidating across a portfolio
• references/promoting-formatting.md — Promoting bespoke visual.json formatting to theme: push-visual CLI, objects vs visualContainerObjects, wildcard vs visual-type, property mapping tables
• references/theme-compliance.md — Systematic audit workflow, stale override classification, severity levels, fix decision tree
• references/visual-type-overrides.md — Override patterns for textbox, image, shape, card, kpi, slicer, lineChart, barChart, tableEx, and matrix

Related Skills

• pbir-cli → references/modifying-theme.md — Full CLI command reference for theme operations (serialize/build, set-colors, set-text-classes, set-formatting, push-visual, fonts, background, icons, diff)
• pbir-cli → references/apply-theme.md — Applying templates, copying themes between reports, clearing visual overrides
• pbir-format (pbip plugin) — Full theme mechanics: ThemeDataColor syntax, filter pane selectors, jq modification patterns, clearing overrides
• pbi-report-design — Report design principles: 3-30-300 rule, layout, spacing, color usage, accessibility