Skills for working with Obsidian vaults and related formats: Obsidian Flavored Markdown, JSON Canvas files, the Obsidian CLI, and Defuddle for clean web content extraction.
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Obsidian Bases is a YAML-driven query layer over vault notes. Think of .base files as live database views, not static tables — they compute and filter in real time against note frontmatter. The key discipline: define your data model in note properties first, then build views on top of it.
When to apply: Creating dynamic views of vault notes by tag, folder, or property; building task trackers, reading lists, or dashboards; or when the user asks for table, cards, or list views in Obsidian. When NOT to apply: One-off note organisation, static Markdown tables, or displaying content that does not come from frontmatter properties.
Consider starting with a simple filter and single table view, then optionally adding formulas and multiple views once the data model is validated.
.base file in the vault with valid YAML contentfilters to select which notes appear (by tag, folder, property, or date)formulas sectiontable, cards, list, or map) with order specifying which properties to displayformula.X without defining X in formulas.base file in Obsidian to confirm the view renders correctly. If it shows a YAML error, check quoting rules belowBase files use the .base extension and contain valid YAML.
# Global filters apply to ALL views in the base
filters:
# Can be a single filter string
# OR a recursive filter object with and/or/not
and: []
or: []
not: []
# Define formula properties that can be used across all views
formulas:
formula_name: 'expression'
# Configure display names and settings for properties
properties:
property_name:
displayName: "Display Name"
formula.formula_name:
displayName: "Formula Display Name"
file.ext:
displayName: "Extension"
# Define custom summary formulas
summaries:
custom_summary_name: 'values.mean().round(3)'
# Define one or more views
views:
- type: table | cards | list | map
name: "View Name"
limit: 10 # Optional: limit results
groupBy: # Optional: group results
property: property_name
direction: ASC | DESC
filters: # View-specific filters
and: []
order: # Properties to display in order
- file.name
- property_name
- formula.formula_name
summaries: # Map properties to summary formulas
property_name: AverageFilters narrow down results. They can be applied globally or per-view.
# Single filter
filters: 'status == "done"'
# AND - all conditions must be true
filters:
and:
- 'status == "done"'
- 'priority > 3'
# OR - any condition can be true
filters:
or:
- 'file.hasTag("book")'
- 'file.hasTag("article")'
# NOT - exclude matching items
filters:
not:
- 'file.hasTag("archived")'
# Nested filters
filters:
or:
- file.hasTag("tag")
- and:
- file.hasTag("book")
- file.hasLink("Textbook")
- not:
- file.hasTag("book")
- file.inFolder("Required Reading")| Operator | Description |
|---|---|
== | equals |
!= | not equal |
> | greater than |
< | less than |
>= | greater than or equal |
<= | less than or equal |
&& | logical and |
|| | logical or |
! | logical not |
note.author or just authorfile.name, file.mtime, etc.formula.my_formula| Property | Type | Description |
|---|---|---|
file.name | String | File name |
file.basename | String | File name without extension |
file.path | String | Full path to file |
file.folder | String | Parent folder path |
file.ext | String | File extension |
file.size | Number | File size in bytes |
file.ctime | Date | Created time |
file.mtime | Date | Modified time |
file.tags | List | All tags in file |
file.links | List | Internal links in file |
file.backlinks | List | Files linking to this file |
file.embeds | List | Embeds in the note |
file.properties | Object | All frontmatter properties |
this KeywordFormulas compute values from properties. Defined in the formulas section.
formulas:
# Simple arithmetic
total: "price * quantity"
# Conditional logic
status_icon: 'if(done, "✅", "⏳")'
# String formatting
formatted_price: 'if(price, price.toFixed(2) + " dollars")'
# Date formatting
created: 'file.ctime.format("YYYY-MM-DD")'
# Calculate days since created (use .days for Duration)
days_old: '(now() - file.ctime).days'
# Calculate days until due date
days_until_due: 'if(due_date, (date(due_date) - today()).days, "")'Most commonly used functions. For the complete reference of all types (Date, String, Number, List, File, Link, Object, RegExp), see FUNCTIONS_REFERENCE.md.
| Function | Signature | Description |
|---|---|---|
date() | date(string): date | Parse string to date (YYYY-MM-DD HH:mm:ss) |
now() | now(): date | Current date and time |
today() | today(): date | Current date (time = 00:00:00) |
if() | if(condition, trueResult, falseResult?) | Conditional |
duration() | duration(string): duration | Parse duration string |
file() | file(path): file | Get file object |
link() | link(path, display?): Link | Create a link |
When subtracting two dates, the result is a Duration type (not a number).
Duration Fields: duration.days, duration.hours, duration.minutes, duration.seconds, duration.milliseconds
IMPORTANT: Duration does NOT support .round(), .floor(), .ceil() directly. Access a numeric field first (like .days), then apply number functions.
# CORRECT: Calculate days between dates
"(date(due_date) - today()).days" # Returns number of days
"(now() - file.ctime).days" # Days since created
"(date(due_date) - today()).days.round(0)" # Rounded days
# WRONG - will cause error:
# "((date(due) - today()) / 86400000).round(0)" # Duration doesn't support division then round# Duration units: y/year/years, M/month/months, d/day/days,
# w/week/weeks, h/hour/hours, m/minute/minutes, s/second/seconds
"now() + \"1 day\"" # Tomorrow
"today() + \"7d\"" # A week from today
"now() - file.ctime" # Returns Duration
"(now() - file.ctime).days" # Get days as numberviews:
- type: table
name: "My Table"
order:
- file.name
- status
- due_date
summaries:
price: Sum
count: Averageviews:
- type: cards
name: "Gallery"
order:
- file.name
- cover_image
- descriptionviews:
- type: list
name: "Simple List"
order:
- file.name
- statusRequires latitude/longitude properties and the Maps community plugin.
views:
- type: map
name: "Locations"
# Map-specific settings for lat/lng properties| Name | Input Type | Description |
|---|---|---|
Average | Number | Mathematical mean |
Min | Number | Smallest number |
Max | Number | Largest number |
Sum | Number | Sum of all numbers |
Range | Number | Max - Min |
Median | Number | Mathematical median |
Stddev | Number | Standard deviation |
Earliest | Date | Earliest date |
Latest | Date | Latest date |
Range | Date | Latest - Earliest |
Checked | Boolean | Count of true values |
Unchecked | Boolean | Count of false values |
Empty | Any | Count of empty values |
Filled | Any | Count of non-empty values |
Unique | Any | Count of unique values |
filters:
and:
- file.hasTag("task")
- 'file.ext == "md"'
formulas:
days_until_due: 'if(due, (date(due) - today()).days, "")'
is_overdue: 'if(due, date(due) < today() && status != "done", false)'
priority_label: 'if(priority == 1, "🔴 High", if(priority == 2, "🟡 Medium", "🟢 Low"))'
properties:
status:
displayName: Status
formula.days_until_due:
displayName: "Days Until Due"
formula.priority_label:
displayName: Priority
views:
- type: table
name: "Active Tasks"
filters:
and:
- 'status != "done"'
order:
- file.name
- status
- formula.priority_label
- due
- formula.days_until_due
groupBy:
property: status
direction: ASC
summaries:
formula.days_until_due: Average
- type: table
name: "Completed"
filters:
and:
- 'status == "done"'
order:
- file.name
- completed_datefilters:
or:
- file.hasTag("book")
- file.hasTag("article")
formulas:
reading_time: 'if(pages, (pages * 2).toString() + " min", "")'
status_icon: 'if(status == "reading", "📖", if(status == "done", "✅", "📚"))'
year_read: 'if(finished_date, date(finished_date).year, "")'
properties:
author:
displayName: Author
formula.status_icon:
displayName: ""
formula.reading_time:
displayName: "Est. Time"
views:
- type: cards
name: "Library"
order:
- cover
- file.name
- author
- formula.status_icon
filters:
not:
- 'status == "dropped"'
- type: table
name: "Reading List"
filters:
and:
- 'status == "to-read"'
order:
- file.name
- author
- pages
- formula.reading_timefilters:
and:
- file.inFolder("Daily Notes")
- '/^\d{4}-\d{2}-\d{2}$/.matches(file.basename)'
formulas:
word_estimate: '(file.size / 5).round(0)'
day_of_week: 'date(file.basename).format("dddd")'
properties:
formula.day_of_week:
displayName: "Day"
formula.word_estimate:
displayName: "~Words"
views:
- type: table
name: "Recent Notes"
limit: 30
order:
- file.name
- formula.day_of_week
- formula.word_estimate
- file.mtimeThese are workflow- and design-level anti-patterns that cause silent failures or runtime errors in Obsidian Bases. Each is distinct from the YAML syntax issues covered in Troubleshooting.
NEVER call property-dependent functions such as date(due_date) without first
checking that the property exists. Calling date(due_date) when due_date is empty
throws a runtime error and the whole formula column goes blank.
WHY: Obsidian Bases evaluates formulas against every note in scope. A single note with a missing property causes the entire formula column to blank out silently for all rows, making data appear lost when it is simply unguarded.
# BAD - crashes when due_date is missing
formulas:
days_until_due: "(date(due_date) - today()).days"# GOOD - guard with if() before accessing the property
formulas:
days_until_due: 'if(due_date, (date(due_date) - today()).days, "")'Always wrap property-dependent expressions in if(property, ..., fallback).
NEVER call .round(), .floor(), or .ceil() directly on the result of a date
subtraction. Date subtraction returns a Duration, not a Number, and Duration does
not expose those methods. Calling them directly causes an error.
# BAD - Duration is not a Number; .round() is undefined on it
formulas:
age: "(now() - file.ctime).round(0)"# GOOD - extract a numeric field first, then round
formulas:
age: "(now() - file.ctime).days.round(0)"Access .days, .hours, .minutes, etc. before applying any Number methods.
WHY: Duration and Number are distinct types. Skipping the field accessor means you are calling a Number method on an object that does not have it, causing a formula error that suppresses output for the entire column.
NEVER reference formula.X in order or properties without a matching key in
the formulas block. If formula.priority appears in order or properties but
priority is not listed under formulas, Obsidian silently drops the column.
No error is shown.
# BAD - formula.priority referenced but never defined
views:
- type: table
order:
- formula.priority# GOOD - define the formula before referencing it
formulas:
priority: 'if(priority == 1, "High", if(priority == 2, "Medium", "Low"))'
views:
- type: table
order:
- formula.priorityAlways verify every formula.X reference has a matching key in formulas.
WHY: Obsidian does not raise an error for undefined formula references — it simply
omits the column. The silent failure makes it easy to spend time debugging data
visibility when the root cause is a missing formulas entry.
NEVER leave strings unquoted when they contain characters that YAML treats as
structural syntax. Characters like :, {, }, [, ], and # are meaningful in
YAML. An unquoted value containing them causes a parse error and the entire base fails
to load.
# BAD - the colon inside the value breaks YAML parsing
properties:
status:
displayName: Status: Active# GOOD - wrap in double quotes
properties:
status:
displayName: "Status: Active"Any string that contains :, {, }, [, ], ,, &, *, #, ?, |, -,
<, >, =, !, %, @, or a backtick must be quoted.
WHY: A YAML parse error prevents the entire .base file from loading at all.
Obsidian shows a generic error with no indication of which line is at fault, making
unquoted special characters one of the hardest classes of mistake to diagnose quickly.
NEVER place status- or state-specific conditions in the top-level filters block
when your base contains views that need to show different subsets of those notes.
A filters block at the top level applies to all views. If you want one view to
show active items and another to show archived ones, a global filter that excludes
archived notes will silently remove them from every view.
# BAD - global filter prevents the "Archived" view from ever showing archived notes
filters: 'file.hasTag("project")'
views:
- type: table
name: "Active"
filters: 'status == "active"'
- type: table
name: "Archived"
filters: 'status == "archived"' # never shows anything — global filter already excluded them# GOOD - global filter contains only the invariant scope; per-view filters handle the rest
filters: 'file.hasTag("project")'
views:
- type: table
name: "Active"
filters: 'status == "active"'
- type: table
name: "Archived"
# remove global archive-exclusion or add the archive tag to the global filter scope
filters: 'status == "archived"'Move status-specific conditions to view-level filters. Keep global filters only for
properties that are truly shared across all views (e.g., folder or tag scope).
WHY: Global filters act as an invisible pre-filter that view-level filters cannot override. Notes excluded at the global level never reach any view, so a view that looks correct in isolation will still silently suppress those records.
NEVER use file.name as a display column in table or cards views when you want
clean note titles. file.name includes the file extension (e.g., My Note.md).
file.basename returns only the title without the extension (e.g., My Note).
Displaying file.name in a table or cards view looks cluttered.
# BAD - shows "Book Title.md" instead of "Book Title"
views:
- type: cards
order:
- file.name
- author# GOOD - shows "Book Title"
views:
- type: cards
order:
- file.basename
- authorUse file.name only when the extension itself is meaningful (e.g., comparing .md vs
.canvas files). For all display purposes, prefer file.basename.
WHY: Every Obsidian note has the .md extension, so file.name in a display
column produces uniformly cluttered output (Title.md, Title.md, ...) with no
benefit. The extension adds visual noise without conveying information.
Embed in Markdown files:
![[MyBase.base]]
<!-- Specific view -->
![[MyBase.base#View Name]]'if(done, "Yes", "No")'"My View Name"defuddle
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