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RegisterExternalEvaluator[sys,evaluator]

registers the evaluator for use as an external evaluator with the language or system sys.

RegisterExternalEvaluator[sys,evaluator,name]

registers the evaluator using the assigned name name.

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Basic Examples  
Scope  
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Possible Issues  
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RegisterExternalEvaluator   

Listing of External Evaluators »

RegisterExternalEvaluator[sys,evaluator]

registers the evaluator for use as an external evaluator with the language or system sys.

RegisterExternalEvaluator[sys,evaluator,name]

registers the evaluator using the assigned name name.

Details

Examples

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Basic Examples  (3)

Register a new NodeJS installation at the location "/usr/local/bin/node":

Wolfram Language code: RegisterExternalEvaluator["NodeJS", "/opt/homebrew/bin/node"]

Use FindExternalEvaluators to see that the NodeJS installation is registered:

Wolfram Language code: FindExternalEvaluators["NodeJS"]

Register a Python installation found at the location "/usr/bin/python3":

Wolfram Language code: RegisterExternalEvaluator["Python", "/usr/bin/python3"]

Use the newly registered Python:

Wolfram Language code: ExternalEvaluate["Python", "import sys; sys.version"]

Register a Python provisioned environment using a name:

Wolfram Language code: RegisterExternalEvaluator[ "Python", <| "Dependencies" -> {"emoji"}, "EnvironmentName" -> "myenv", "PythonRuntime" -> "3.11" |>, "my-env" ]

Use the newly registered environment by referring to it by name:

Wolfram Language code: ExternalEvaluate[{"Python", "Name" -> "my-env"}, "import emoji; emoji.emojize('Emojis are :thumbs_up:')"]

Scope  (2)

Register a Python installation using a name:

Wolfram Language code: RegisterExternalEvaluator["Python", "/usr/bin/python3", "my-main-env"]

Use the newly registered environment:

Wolfram Language code: ExternalEvaluate[ {"Python", "EvaluatorID" -> "my-main-env"}, "import sys; sys.executable" ]

The name can also be found when using ExternalEvaluators:

Wolfram Language code: Map[#["EvaluatorID"]&, ExternalEvaluators["Python"]]

Define a reference to a database using SQLite:

Wolfram Language code: db = DatabaseReference[FindFile["ExampleData/ecommerce-database.sqlite"]]

Register the database using RegisterExternalEvaluator:

Wolfram Language code: RegisterExternalEvaluator["SQL", db]
Wolfram Language code: FindExternalEvaluators["SQL"]

When using ExternalEvaluate, "SQL" will use the most recently registered database:

Wolfram Language code: ExternalEvaluate["SQL", "select sqlite_version() as version, date('now') as now"]

To unregister the database, use UnregisterExternalEvaluator:

Wolfram Language code: UnregisterExternalEvaluator["SQL", DatabaseReference[FindFile["ExampleData/ecommerce-database.sqlite"]]]

Properties & Relations  (1)

Unregister all external evaluators with UnregisterExternalEvaluator:

Wolfram Language code: UnregisterExternalEvaluator["Python", All]

ExternalEvaluate will attempt to provide an evaluator when you do not have registered evaluators anymore:

Wolfram Language code: ExternalEvaluate["Python", "2+2"]

For the "Python" evaluator, a new installation is created under $UserBaseDirectory:

Wolfram Language code: ExternalEvaluate["Python", "import sys; sys.executable"]

Possible Issues  (1)

Register a Python installation using a name:

Wolfram Language code: RegisterExternalEvaluator["Python", "/opt/homebrew/bin/python3", "my-main-env"]

Registering a different Python installation using the same name will override the previous registration:

Wolfram Language code: RegisterExternalEvaluator["Python", "/opt/homebrew/bin/python3", "my-main-env"]

The latest installation is now registered:

Wolfram Language code: ExternalEvaluators["Python"]
Wolfram Research (2017), RegisterExternalEvaluator, Wolfram Language function, https://reference.wolfram.com/language/ref/RegisterExternalEvaluator.html (updated 2020).

Text

Wolfram Research (2017), RegisterExternalEvaluator, Wolfram Language function, https://reference.wolfram.com/language/ref/RegisterExternalEvaluator.html (updated 2020).

CMS

Wolfram Language. 2017. "RegisterExternalEvaluator." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/RegisterExternalEvaluator.html.

APA

Wolfram Language. (2017). RegisterExternalEvaluator. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/RegisterExternalEvaluator.html

BibTeX

@misc{reference.wolfram_2026_registerexternalevaluator, author="Wolfram Research", title="{RegisterExternalEvaluator}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/RegisterExternalEvaluator.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_registerexternalevaluator, organization={Wolfram Research}, title={RegisterExternalEvaluator}, year={2020}, url={https://reference.wolfram.com/language/ref/RegisterExternalEvaluator.html}, note=[Accessed: 12-June-2026]}