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 service's CPU count, based on its compute plan.
For example, this value is 0.5 for the 0.5c-512mb compute plan and 2 for the 2c-4g compute plan. 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 CPU count for the service's compute plan.
For example, this value is 1 for the 0.5c-512mb compute plan and 2 for the 2c-4g compute plan. 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 CPU count for the service's compute plan.
For example, this value is 1 for the 0.5c-512mb compute plan and 2 for the 2c-4g compute plan. 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
ERLANG_VERSION
Node.js
SKIP_INSTALL_DEPS
Set this to true to skip running yarn/npm install during build.