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coc-yaml

Neoclide

yaml extension for coc.nvim

Installation CommandVim prompt
:CocInstall coc-yaml
GitHub owner
Neoclide
Version
v1.9.3
npm package
coc-yaml
Requirements
coc ^0.0.80
License
MIT
Repository
GitHub
npm latest published 2026-08-07Registry checked 2026-08-23Registry summary

Published Package Summary

coc-yaml

Fork of vscode-yaml that works with coc.nvim

Install

In your vim/neovim, run command:

:CocInstall coc-yaml

Features

  1. YAML validation:
    • Detects whether the entire file is valid yaml
    • Detects errors such as:
      • Node is not found
      • Node has an invalid key node type
      • Node has an invalid type
      • Node is not a valid child node
  2. Document Outlining (:CocOutline):
    • Provides the document outlining of all completed nodes in the file
  3. Auto completion:
    • Auto completes on all commands
    • Scalar nodes autocomplete to schema's defaults if they exist
  4. Hover support:
    • Hovering over a node shows description if provided by schema
  5. Formatter:
    • Allows for formatting the current file
    • On type formatting auto indent for array items

Auto completion and hover support are provided by the schema. Please refer to Language Server Settings to setup a schema

YAML version support

Starting from 1.0.0 the extension uses eemeli/yaml as the new YAML parser, which strictly enforces the specified YAML spec version. Default YAML spec version is 1.2, it can be changed with yaml.yamlVersion setting.

Adding custom tags

In order to use the custom tags in your YAML file you need to first specify the custom tags in the setting of your code editor. For example, you can have the following custom tags:

"yaml.customTags": [
    "!Scalar-example scalar",
    "!Seq-example sequence",
    "!Mapping-example mapping"
]

The !Scalar-example would map to a scalar custom tag, the !Seq-example would map to a sequence custom tag, the !Mapping-example would map to a mapping custom tag.

You can then use the newly defined custom tags inside the YAML file:

some_key: !Scalar-example some_value
some_sequence: !Seq-example
  - some_seq_key_1: some_seq_value_1
  - some_seq_key_2: some_seq_value_2
some_mapping: !Mapping-example
  some_mapping_key_1: some_mapping_value_1
  some_mapping_key_2: some_mapping_value_2

Associating schemas

YAML Language support uses JSON Schemas to understand the shape of a YAML file, including its value sets, defaults and descriptions. The schema support is shipped with JSON Schema Draft 7.

We support schemas provided through JSON Schema Store. However, schemas can also be defined in a workspace.

The association of a YAML file to a schema can be done either in the YAML file itself using a modeline or in the User or Workspace settings under the property yaml.schemas.

Associating a schema in the YAML file

It is possible to specify a yaml schema using a modeline.

# yaml-language-server: $schema=<urlToTheSchema>

Associating a schema to a glob pattern via yaml.schemas:

yaml.schemas applies a schema to a file. In other words, the schema (placed on the left) is applied to the glob pattern on the right. Your schema can be local or online. Your schema must be a relative path and not an absolute path. The entrance point for yaml.schemas is location in user and workspace settings

When associating a schema it should follow the format below

"yaml.schemas": {
    "url": "globPattern",
    "Kubernetes": "globPattern"
}

e.g.

yaml.schemas: {
    "https://json.schemastore.org/composer": "/*"
}

e.g.

yaml.schemas: {
    "kubernetes": "/myYamlFile.yaml"
}

e.g.

yaml.schemas: {
    "https://json.schemastore.org/composer": "/*",
    "kubernetes": "/myYamlFile.yaml"
}

On Windows with full path:

yaml.schemas: {
    "C:\\Users\\user\\Documents\\custom_schema.json": "someFilePattern.yaml",
}

On Mac/Linux with full path:

yaml.schemas: {
    "/home/user/custom_schema.json": "someFilePattern.yaml",
}

Since 0.11.0 YAML Schemas can be used for validation:

 "/home/user/custom_schema.yaml": "someFilePattern.yaml"

A schema can be associated with multiple globs using a json array, e.g.

yaml.schemas: {
    "kubernetes": ["filePattern1.yaml", "filePattern2.yaml"]
}

e.g.

"yaml.schemas": {
    "http://json.schemastore.org/composer": ["/*"],
    "file:///home/johnd/some-schema.json": ["some.yaml"],
    "../relative/path/schema.json": ["/config*.yaml"],
    "/Users/johnd/some-schema.json": ["some.yaml"],
}

e.g.

"yaml.schemas": {
    "kubernetes": ["/myYamlFile.yaml"]
}

e.g.

"yaml.schemas": {
    "http://json.schemastore.org/composer": ["/*"],
    "kubernetes": ["/myYamlFile.yaml"]
}
Multi root schema association:

You can also use relative paths when working with multi root workspaces.

Suppose you have a multi root workspace that is laid out like:

My_first_project:
   test.yaml
   my_schema.json
My_second_project:
   test2.yaml
   my_schema2.json

You must then associate schemas relative to the root of the multi root workspace project.

"yaml.schemas": {
    "My_first_project/my_schema.json": "test.yaml",
    "My_second_project/my_schema2.json": "test2.yaml"
}

yaml.schemas allows you to specify json schemas that you want to validate against the yaml that you write. Kubernetes is a reserved keyword field. It does not require a url as the language server will provide that. You just need the keyword kubernetes and a glob pattern.

Mapping a schema in an extension

  • Supports yamlValidation point which allows you to contribute a schema for a specific type of yaml file (Similar to jsonValidation) e.g.
{
  "contributes": {
    "yamlValidation": [
      {
        "fileMatch": "yourfile.yml",
        "url": "./schema.json"
      }
    ]
  }
}

Contribute

Consider support coc.nvim development on Patreon or PayPal:

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Read the complete README
  • yaml extension for coc.nvim
Activation Events
  • onLanguage:yaml
Developer Resources

Want to build, test, or contribute to coc.nvim extensions? Explore our official SDK and testing toolkits.

Open Developer Guide

Version History

Published with coc-yaml@1.9.3 as CHANGELOG.md.

Open source file

1.7.1

  • And yaml.selectSchema command.

1.7.0

  • Add configuration yaml.disableDefaultProperties.
  • Add status bar item support for resolved schema.
  • Support cache fetched schema result by etag.
  • Support show information when max items exceed.
  • Support JSONSchemaDocumentContentProvider for custom schema: json-schema.