Bases syntax

When you create a base in Obsidian, it is saved as a .base file. Bases are typically edited through the app interface, but you can also edit the underlying syntax directly or write it in a base code block embedded in a Markdown note. Bases syntax is YAML-based. Filters and formulas share the same expression language.

Complete example

Here is a fully configured .base file:

filters:
  or:
    - file.hasTag("tag")
    - and:
        - file.hasTag("book")
        - file.hasLink("Textbook")
    - not:
        - file.hasTag("book")
        - file.inFolder("Required Reading")
formulas:
  formatted_price: 'if(price, price.toFixed(2) + " dollars")'
  ppu: "(price / age).toFixed(2)"
properties:
  status:
    displayName: Status
  formula.formatted_price:
    displayName: "Price"
  file.ext:
    displayName: Extension
summaries:
  customAverage: 'values.mean().round(3)'
views:
  - type: table
    name: "My table"
    limit: 10
    groupBy:
      property: note.age
      direction: DESC
    filters:
      and:
        - 'status != "done"'
        - or:
            - "formula.ppu > 5"
            - "price > 2.1"
    order:
      - file.name
      - file.ext
      - note.age
      - formula.ppu
      - formula.formatted_price
    summaries:
      formula.ppu: Average

Sections

`filters`

The filters section narrows which files the base includes. Without filters, a base shows every file in your vault. Filters can be applied at two levels:

Global — under the top-level filters key. Applies to all views.
Per-view — inside an individual view’s filters key. Applies only to that view.

Both levels are combined with AND when evaluating a view.

# Simple filter
filters:
  and:
    - file.hasTag("tag")

# Complex filter with nested logic
filters:
  or:
    - file.hasTag("tag")
    - and:
        - file.hasTag("book")
        - file.hasLink("Textbook")
    - not:
        - file.hasTag("book")
        - file.inFolder("Required Reading")

A filter statement is any expression that evaluates to truthy or falsey for a given file. This includes comparisons and function calls.

`formulas`

The formulas section defines computed properties available across all views:

formulas:
  formatted_price: 'if(price, price.toFixed(2) + " dollars")'
  ppu: "(price / age).toFixed(2)"

Formulas are stored as strings in YAML. Use nested quotes for text literals. A formula’s output type is determined by the data and functions used — formulas are not constrained to strings at runtime. Reference property types in formulas:

Type	Syntax	Example
Note property	`property` or `note.property`	`price`
File property	`file.name`, `file.size`	`file.mtime`
Another formula	`formula.name`	`formula.ppu`

`properties`

The properties section stores display configuration for properties:

properties:
  status:
    displayName: Status
  formula.formatted_price:
    displayName: "Price"
  file.ext:
    displayName: Extension

Display names are used in column headers and UI labels. They are not used in filters or formulas.

`summaries`

The summaries section defines custom summary formulas. In the values expression, values is a list of all values for that property across every row in the result set:

summaries:
  customAverage: 'values.mean().round(3)'

Default summary formulas are also available without defining them here:

Name	Input type	Description
Average	Number	Mean of all values
Min	Number	Smallest value
Max	Number	Largest value
Sum	Number	Total of all values
Range	Number	Difference between max and min
Median	Number	Median value
Stddev	Number	Standard deviation
Earliest	Date	Oldest date
Latest	Date	Most recent date
Range	Date	Difference between earliest and latest
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 distinct values

`views`

The views section is a list of view configurations:

views:
  - type: table
    name: "My table"
    limit: 10
    groupBy:
      property: note.age
      direction: DESC
    filters:
      and:
        - 'status != "done"'
    order:
      - file.name
      - note.age
    summaries:
      formula.ppu: Average

Key	Description
`type`	Layout type: `table`, `list`, `cards`, `map`
`name`	Display name for the view. Used to select a default view when embedding.
`limit`	Maximum number of rows to display.
`filters`	View-specific filters (same syntax as global `filters`).
`groupBy`	Property and direction to group results.
`order`	List of property names defining column order.
`summaries`	Map of property names to summary formula names.

Properties in bases

Bases work with three types of properties:

Note properties

Stored in the YAML frontmatter of Markdown files. Access with property_name or note.property_name:

author == "Ursula Le Guin"
note.status == "Done"

File properties

Built-in properties available for all file types:

Property	Type	Description
`file.name`	String	File name including extension
`file.basename`	String	File name without extension
`file.path`	String	Full path relative to vault root
`file.folder`	String	Path to the parent folder
`file.ext`	String	File extension
`file.size`	Number	File size in bytes
`file.tags`	List	Tags including inline tags
`file.links`	List	Internal links within the file
`file.ctime`	Date	Creation timestamp
`file.mtime`	Date	Last-modified timestamp
`file.properties`	Object	All frontmatter properties

`this` — context-aware file reference

Use this to reference the file where the base is displayed:

Opened as a file: this refers to the .base file itself.
Embedded in a note: this refers to the embedding note.
In a sidebar: this refers to the active file in the main content area.

Example — replicate the backlinks panel:

filters:
  and:
    - file.hasLink(this.file)

Operators

Arithmetic

Operator	Description
`+`	Add
`-`	Subtract
`*`	Multiply
`/`	Divide
`%`	Modulo
`( )`	Parentheses (grouping)

Comparison

Operator	Description
`==`	Equals
`!=`	Not equal
`>`	Greater than
`<`	Less than
`>=`	Greater than or equal to
`<=`	Less than or equal to

Boolean

Operator	Description
`!`	Logical not
`&&`	Logical and
`\|\|`	Logical or

Date arithmetic

Add or subtract durations from dates using string suffixes:

now() + "1 day"
file.mtime > now() - "1 week"
date("2024-12-01") + "1M" + "4h" + "3m"

Unit	Accepted formats
Year	`y`, `year`, `years`
Month	`M`, `month`, `months`
Day	`d`, `day`, `days`
Week	`w`, `week`, `weeks`
Hour	`h`, `hour`, `hours`
Minute	`m`, `minute`, `minutes`
Second	`s`, `second`, `seconds`

Subtracting two dates returns the difference in milliseconds.

Types

Type	Notes
String	Enclosed in single or double quotes: `"hello"`, `'world'`
Number	Written as digits, optionally in parentheses: `1`, `(2.5)`
Boolean	`true` or `false` (no quotes)
Date	Created with `date()`, `today()`, or `now()`
List	Access elements with `property[0]` (0-based index)
Object	Access values with `property.key` or `property["key"]`
Link	Wikilinks in frontmatter are automatically recognized; construct with `link("path")`

Core Plugins

Bases

User Interface

Extending Obsidian

Complete example

Sections

`filters`

`formulas`

`properties`

`summaries`

`views`

Properties in bases

Note properties

File properties

`this` — context-aware file reference

Operators

Arithmetic

Comparison

Boolean

Date arithmetic

Types

Build docs developers (and LLMs) love

Core Plugins

Bases

User Interface

Extending Obsidian

Documentation Index

​Complete example

​Sections

​filters

​formulas

​properties

​summaries

​views

​Properties in bases

​Note properties

​File properties

​this — context-aware file reference

​Operators

​Arithmetic

​Comparison

​Boolean

​Date arithmetic

​Types

Build docs developers (and LLMs) love

Complete example

Sections

`filters`

`formulas`

`properties`

`summaries`

`views`

Properties in bases

Note properties

File properties

`this` — context-aware file reference

Operators

Arithmetic

Comparison

Boolean

Date arithmetic

Types