Any extension you want available to the project running inside the devcontainer you should have on the list. To quickly add extensions from your locally installed extensions. Inside the running dev container you can click the gear icon and select “Add to devcontainer.json” then rebuild the container. Answer from tipsdown on reddit.com
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Cursor
forum.cursor.com › support › help
Extensions listed in `devcontainer.json` not installed into Remote Extension Host - Help - Cursor - Community Forum
July 25, 2025 - Describe the Bug In my .vscode/extensions.json and .devcontainer/devcontainer.json files I list the same extensions: "extensions": [ "anysphere.cursorpyright", "anysphere.remote-containers", "batisteo.vscode-django", "csharpier.csharpier-vscode", "davidanson.vscode-markdownlint", "eamodio.gitlens", "editorconfig.editorconfig", "eriklynd.json-tools", "esbenp.prettier-vscode", "humao.rest-client", "idleberg.innosetup", "mechatroner.rainbow-csv", "ms-python.black-formatt...
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GitHub
github.com › microsoft › vscode-remote-release › issues › 8097
Extensions defined in devcontainer.json are not installing · Issue #8097 · microsoft/vscode-remote-release
February 24, 2023 - "vscode": { // Set *default* container specific settings.json values on container create. "settings": { "editor.formatOnSave": true, "files.insertFinalNewline": true, "[makefile]": { "editor.insertSpaces": false, "editor.detectIndentation": false } }, // Add the IDs of extensions you want installed when the container is created.
Author   orolega
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Visual Studio Code
code.visualstudio.com › docs › devcontainers › containers
Developing inside a Container
November 3, 2021 - While you can edit your ... that you do not want installed in your dev container, you can opt out by listing the extension with a minus sign....
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Reddit
reddit.com › r/vscode › what kind of extensions should be installed inside a dev container?
r/vscode on Reddit: What kind of extensions should be installed inside a Dev Container?
November 7, 2023 -

Note: This is not asking for extension recommendations.

I recently started exploring the use of Dev Containers for my next Python+NodeJS+PostgreSQL project, and am trying to understand the customizations => extensions part of .devcontainer.json. For example, after auto-generating the configuration file, this is what's in there currently:

"customizations": {
    "vscode": {
        "extensions":["ms-python.python", "njpwerner.autodocstring"]
    }
}

How do I evaluate which other extensions currently installed in the host need to be installed locally inside the container, and which don't?

Top answer
1 of 3
13

According to the Visual Studio Code documentation, the two files need to be located in a directory .devcontainer in the workspace root.

I still had issues installing the extensions while working from behind a corporate proxy. The solution was to give the container access to the proxy server:

If you use an authenticating proxy like Cntlm on your local machine, configure it to listen on 172.17.0.1 (the Docker interface). Then define the http_proxy and https_proxy environment variables for the container. For example, in devcontainer.json:

"containerEnv": { 
  "http_proxy": "http://172.17.0.1:3128",
  "https_proxy": "http://172.17.0.1:3128"
}

Or in docker-compose.yaml

services:
  devcontainer:
    environment:
      http_proxy: http://172.17.0.1:3128
      https_proxy: http://172.17.0.1:3128

Or configure docker-compose.yaml to make the container use the host network:

services:
  devcontainer:
    network_mode: host

Then you can just pass the same proxy variables into the container as used on the host. For example, in the docker-compose.yaml:

services:
  devcontainer:
    environment:
      http_proxy: $http_proxy
      https_proxy: $https_proxy

If you are not using a local, but rather a remote proxy inside of your network, you can do the latter regardless of the container's network configuration (host or default).

2 of 3
2

I also have issues installing the extensions while working from behind a corporate proxy. The solution was to give the container access to the proxy server and set HTTP proxy strict SSL:

"settings": {
    "http.proxy": "(your_proxy_host:port)",
    "http.proxyStrictSSL": false
},
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Reddit
reddit.com › r/vscode › extensions in devcontainer.json are not automatically installed
r/vscode on Reddit: Extensions in devcontainer.json are not automatically installed
November 27, 2024 -

Hello, I'm working on a project using Docker and VS Code. When I build my docker image and run a container with the docker-compose.yml configuration, it works just fine, but when I try to add some extensions to the container using the devcontainer.json, I get the pop-up to reopen my workspace in the container, but there are no extensions installed. I am working with the latest VS Code version (1.95.3) in Windows 11. My image is built over an Ubuntu 22.04 LTS image. I've seen some Github issues related to mine but it doesnt seem to work for me.

https://github.com/microsoft/vscode-remote-release/issues/8097

https://stackoverflow.com/questions/75562662/vscode-dev-container-doesnt-install-extensions-behind-corporate-proxy

https://github.com/microsoft/vscode-remote-release/issues/6268

This is my devcontainer.json:

{
    "name": "vcg_dev",
    "dockerComposeFile": ["../docker-compose.yml"],
    "service": "ros2",
    "workspaceFolder": "/workspace",
    "customizations": {
        "vscode": {
            "extensions": [
                "ms-python.python",
                "ms-python.vscode-pylance",
                "ms-toolsai.jupyter",
                "ms-vscode.cpptools",
                "ms-vscode.cmake-tools",
                "twxs.cmake",
                "ms-iot.vscode-ros",
                "smilerobotics.urdf",
                "eamodio.gitlens",
                "ms-azuretools.vscode-docker",
                "ms-vscode.remote-containers",
                "redhat.vscode-yaml",
                "yzhang.markdown-all-in-one",
                "streetsidesoftware.code-spell-checker",
                "wayou.vscode-todo-highlight",
                "gruntfuggly.todo-tree"
            ],
            "settings": {
                "python.defaultInterpreterPath": "/usr/bin/python3",
                "python.analysis.typeCheckingMode": "basic",
                "C_Cpp.default.configurationProvider": "ms-vscode.cmake-tools",
                "cmake.configureOnOpen": true,
                "extensions.verifySignature": false
            }
        }
    },
    "remoteUser": "root",
    "overrideCommand": false,
    "forwardPorts": [8765]
}

Any help would be very appreciated!

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GitHub
github.com › microsoft › vscode-remote-release › issues › 9616
Devcontainer extensions not installed when using --platform on the image · Issue #9616 · microsoft/vscode-remote-release
February 29, 2024 - 2. Reference you Dockerfile in your devcontainer.json 3. Add extensions to the devcontainer.json · 4. Rebuild container 5. Notice extensions are not installed and keep showing "Installing" Does this issue occur when you try this locally?: Yes Does this issue occur when you try this locally and all extensions are disabled?: Not sure what is meant by "all extensions are disabled" Reactions are currently unavailable ·
Author   xenoliss
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GitHub
github.com › microsoft › vscode-remote-release › issues › 6268
extensions in `devcontainer.json` are not automatically installed · Issue #6268 · microsoft/vscode-remote-release
February 2, 2022 - Extensions defined in .devcontainer/devcontainer.json are not installed during the container build process---but they can be installed with the GUI later on (as indicated in the last part of the attached log).
Author   JackCaster
Find elsewhere
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GitHub
github.com › loft-sh › devpod › issues › 1965
Cursor IDE: extensions from devcontainer.json not installed - server binary path mismatch · Issue #1965 · loft-sh/devpod
March 2, 2026 - Create a workspace with extensions in devcontainer.json: "customizations": { "vscode": { "extensions": ["golang.go", "esbenp.prettier-vscode"] } } ... DevPod 0.3.7 fails to install extensions with VSCode Insiders #774 — Same class of bug (hardcoded path mismatch) for VS Code Insiders · Add support for cursor.com IDE (vscode compatible fork) #1127 — Original Cursor support request · Error opening vscode via cli: couldn't find the code binary [Cursor] #1335 — Cursor binary not found (fixed in 0.5.22, but extension install path was not addressed)
Author   ofirzyg
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Stack Overflow
stackoverflow.com › questions › 78650817 › vs-code-devcontainer-some-extensions-not-installed
docker - VS Code devcontainer some extensions not installed - Stack Overflow
I have also seen this issue and don't understand it. Despite "ms-python.debugpy" being declared in the .devcontainer.json customizations.vscode.extensions , it is not installed!
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GitHub
github.com › microsoft › vscode › issues › 120332
Remote extensions are not installed automatically from devcontainer.json · Issue #120332 · microsoft/vscode
Expected result: Extensions are installed in the container Actual result: No extensions are installed.
Author   ghost
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Stack Overflow
stackoverflow.com › questions › 79188324 › issue-with-installing-vscode-extensions-through-devcontainer-json-174
Issue with installing vscode extensions through devcontainer.json #174 - Stack Overflow
// "postStartCommand": "yarn install && yarn run dev-container", // Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root. //"remoteUser": "node", "features": { "ghcr.io/devcontainers/features/git:1": { "version": "os-provided" } } }``` ... Automating Configuration of devcontainer.json in GitHub Codespaces with Frequently Used VSCode Extensions
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GitHub
github.com › microsoft › vscode-remote-release › issues › 9141
Dev Container Doesn't Install Extensions with 1.82 · Issue #9141 · microsoft/vscode-remote-release
September 28, 2023 - "postCreateCommand": "mkdir -p /root/cert && chown root /root/cert && cp /etc/ssl/certs/ca-certificates.crt /root/cert/ca-certificates.crt && pip install -r /app/requirements.local.txt", "containerEnv": {"NODE_EXTRA_CA_CERTS": "/etc/ssl/certs/ca-certificates.crt"}, // this fixes the vscode extensions not installing "forwardPorts": [8080:5000], "remoteUser": "root" }
Author   JamesWordie
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DEV Community
dev.to › azure › extending-vscode-dev-container-features-4n71
Extending VSCode Dev Container Features - DEV Community
December 2, 2022 - There are a few options for this... Easiest thing I can do is update my Dockerfile to include the az extension add commands. This is a good option, but it requires me to write the az extension add command for every extension I need.
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GitHub
github.com › microsoft › vscode-remote-release › issues › 9100
devcontainer - extensions are not installed · Issue #9100 · microsoft/vscode-remote-release
October 12, 2023 - Logs: uploaded Show Container log. devcontainer extensions not installed.txt I have been working with VSCODE since last year and I have tried devcontainer to install the extensions for a while, but no release has fixed this yet for me. ... Tested with Default profile & different extensions. Create devcontainer.json with any extension (manually added in my case)
Author   borjamunozf
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GitHub
github.com › microsoft › vscode-remote-release › issues › 4839
Extensions specified in devcontainer.json not being installed · Issue #4839 · microsoft/vscode-remote-release
April 6, 2021 - Installing extensions... [15:10:18] Error: connect ECONNREFUSED 13.107.42.18:443 at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1141:16) { errno: 'ECONNREFUSED', code: 'ECONNREFUSED', syscall: 'connect', address: '13.107.42.18', port: 443 } Removing the --force-disable-user-env switch appears to successfully download the extensions (though they don't work when run from the terminal like this; I'm guessing they're loaded into the wrong extension host), so it's possibly some sort of problem with our proxy setup.
Author   rjra100