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    Default Environment Variables

    Render automatically sets the values of certain environment variables for your service.

    Unless otherwise noted, these environment variables are available at both build time and runtime.

    Environment variable values are always strings.

    In your application logic, perform any necessary conversions for variable values that represent other data types, such as "false" or "10000".

    By runtime

    All runtimes

    IS_PULL_REQUEST

    This value is true for pull request previews and false otherwise.

    Note that these are the string values "true" and "false". Convert to booleans as needed.

    RENDER

    This value is always true. Your code can check this value to detect whether it's running on Render.

    RENDER_CPU_COUNT

    The number of CPUs available for this service, based on its instance type.

    For example, this value is 0.5 for the Starter instance type and 2 for the Pro instance type. Note that these are the string values "0.5" and "2". Convert to numbers as needed.

    RENDER_DISCOVERY_SERVICE

    The Render DNS name used to discover all running instances of a scaled service. Has the format $RENDER_SERVICE_NAME-discovery.

    RENDER_EXTERNAL_HOSTNAME

    For a web service or static site, this is the service's onrender.com hostname (such as myapp.onrender.com).

    For other service types, this value is empty.

    RENDER_EXTERNAL_URL

    For a web service or static site, this is the service's full onrender.com URL (such as https://myapp.onrender.com).

    For other service types, this value is empty.

    RENDER_GIT_BRANCH

    The Git branch for a service or deploy.

    RENDER_GIT_COMMIT

    The commit SHA for a service or deploy.

    RENDER_GIT_REPO_SLUG

    Has the format $username/$reponame.

    RENDER_INSTANCE_ID

    The unique identifier of the current service instance. Useful for scaled services with multiple instances.

    RENDER_SERVICE_ID

    The service's unique identifier. Used in the Render API.

    RENDER_SERVICE_NAME

    A unique, human-readable identifier for a service.

    RENDER_SERVICE_TYPE

    The current service's type. One of web, pserv, cron, worker, static.

    RENDER_WEB_CONCURRENCY

    For a web service or private service, this is the recommended number of concurrent web processes for handling requests. This is based on the number of CPUs available on the service's instance type.

    For example, this value is 1 for the Starter instance type and 2 for the Pro instance type. Note that these are the string values "1" and "2". Convert to numbers as needed.

    This is only available at runtime. At build time or for other service types, this value is empty.

    WEB_CONCURRENCY

    For a web service or private service created after December 8th 2025, this defaults to the recommended number of concurrent web processes for handling requests. This is based on the number of CPUs available on the service's instance type.

    For example, this value is 1 for the Starter instance type and 2 for the Pro instance type. Note that these are the string values "1" and "2". Convert to numbers as needed.

    This is only available at runtime. At build time, for other service types, or for web and private services created before the cutoff date, this value is empty.

    Other environment variables starting with RENDER_ might be present in your build and runtime environments.

    However, variables not listed above are strictly for internal use and might change without warning.

    Docker

    Render does not provide additional environment variables on top of what's listed under All runtimes.

    Elixir

    MIX_ENV

    prod

    RELEASE_DISTRIBUTION

    name

    Go

    GO111MODULE

    on

    GOPATH

    /opt/render/project/go

    Node.js

    NODE_ENV

    production (runtime only)

    NODE_MODULES_CACHE

    true

    Python 3

    CI

    true (build time only)

    FORWARDED_ALLOW_IPS

    *

    GUNICORN_CMD_ARGS

    --preload --access-logfile - --bind=0.0.0.0:10000

    PIPENV_YES

    true

    VENV_ROOT

    /opt/render/project/src/.venv

    Ruby

    BUNDLE_APP_CONFIG

    /opt/render/project/.gems

    BUNDLE_BIN

    /opt/render/project/.gems/bin

    BUNDLE_DEPLOYMENT

    true

    BUNDLE_PATH

    /opt/render/project/.gems

    GEM_PATH

    /opt/render/project/.gems

    MALLOC_ARENA_MAX

    2

    PASSENGER_ENGINE

    builtin

    PASSENGER_ENVIRONMENT

    production

    PASSENGER_PORT

    10000

    PIDFILE

    /tmp/puma-server.pid

    RAILS_ENV

    production

    RAILS_SERVE_STATIC_FILES

    true

    RAILS_LOG_TO_STDOUT

    true

    Rust

    CARGO_HOME

    /opt/render/project/.cargo

    ROCKET_ENV

    prod

    ROCKET_PORT

    10000 (runtime only)

    RUSTUP_HOME

    /opt/render/project/.rustup

    Optional environment variables

    You can set these environment variables to modify the default behavior for your services.

    All runtimes

    PORT

    For web services, specify the port that your HTTP server binds to.

    The default port is 10000.

    Elixir

    ELIXIR_VERSION

    See Setting Your Elixir and Erlang Versions.

    ERLANG_VERSION

    See Setting Your Elixir and Erlang Versions.

    Node.js

    SKIP_INSTALL_DEPS

    Set this to true to skip running yarn/npm install during build.

    NODE_VERSION

    See Setting Your Node.js Version.

    BUN_VERSION

    See Setting Your Bun Version.

    Python 3

    PYTHON_VERSION

    See Setting Your Python Version.

    POETRY_VERSION

    See Setting Your Poetry Version.

    UV_VERSION

    See Setting Your uv Version.

    Rust

    RUSTUP_TOOLCHAIN

    See Specifying a Rust Toolchain.

    How to set environment variables

    See Environment Variables and Secrets.