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Reusable code uploads

Upload a code blob once and reference it from many submissions.

Last updated June 3, 2026

Some workflows reuse the same fitness function or callback across many runs. Instead of pasting the source into every submission body, upload it once as a code blob and reference it by id.

The client.code_uploads resource exposes this.

Upload a code blob

upload = client.code_uploads.create(
    content=(
        "def fitness_func(ga, sol, idx):\n"
        "    return -sum(s*s for s in sol)\n"
    ),
)

print(upload.code_id, upload.content_size)

An upload just stores the source and hands back a code_id. It is role-agnostic: you decide which role it fills when you reference it from a submission.

REST equivalent: POST /api/v1/code-uploads/.

Use a code blob in a submission

Reference an upload with the matching <role>_id parameter, passing the code_id you got back. Because the source lives on the server, the SDK can't read it to fill in the entry symbol for you, so pass <role>_entry yourself (the top-level name to call):

client.submissions.create(
    name="reused fitness",
    fitness_func_id=upload.code_id,
    fitness_func_entry="fitness_func",
    num_genes=5,
    num_generations=50,
    sol_per_pop=30,
)

The server resolves the blob, applies it as the fitness function, and runs the job. For the libraries available to imported code, see Libraries you can import.

Fetch an upload

blob = client.code_uploads.get(upload.code_id)
print(blob.code_id, blob.content_size, blob.is_expired)

REST equivalent: GET /api/v1/code-uploads/<id>.

What a CodeUpload contains

Attribute Type What it is
code_id str Blob identifier. Pass it as a <role>_id parameter (for example fitness_func_id) when creating submissions.
content str \| None The stored source. Returned when you fetch a single upload.
content_size int \| None Size of the source in bytes.
content_sha256 str \| None SHA-256 of the source.
created_at datetime \| None When the upload was saved.
expires_at datetime \| None When the upload is scheduled to expire.
is_expired bool \| None Whether the upload has passed its expiry.
raw dict The full server response, preserved for forward compatibility.
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