@Marvin: How could I estimate the parameters size, so I could keep it under the 512kb limit?

✅ thought for 63.7 seconds

fwiw i would suggest that if you're close, you should probably be passing a reference to whatever is so large

Great question. The safest way is to measure the size of your parameters after JSON serialization (the way they’re sent to Prefect’s API). In practice: - Use orjson if you can (it’s what FastAPI/Prefect commonly use under the hood) and count the bytes - Otherwise, use the standard json module with compact separators and UTF‑8 encoding Here’s a small helper you can use anywhere you assemble your params (before submitting the flow run or deployment):

def estimate_param_size_bytes(params, prefer_orjson=True):
    try:
        if prefer_orjson:
            import orjson
            return len(orjson.dumps(params))
    except Exception:
        pass

    import json
    # compact separators minimize size; ensure_ascii=False keeps UTF-8 efficient
    payload = json.dumps(params, separators=(",", ":"), ensure_ascii=False).encode("utf-8")
    return len(payload)

def estimate_param_size_kb(params):
    return estimate_param_size_bytes(params) / 1024

# Example
params = {
    "small_flag": True,
    "names": ["alice", "bob"],
    # ... your params ...
}
size_kb = estimate_param_size_kb(params)
print(f"Estimated serialized size: {size_kb:.2f} KiB")

Tips to stay under 512 KiB: - Pass references, not data: upload large payloads (dataframes, long lists, models) to object storage (S3/GCS/Azure) and pass a URI or key instead. - Avoid base64 unless you also compress: base64 adds ~33% overhead. If you must embed data, compress first (e.g., zlib) and then base64. - Remove whitespace and redundant fields; prefer compact strings and IDs over verbose structures. - Keep a margin (e.g., target < 450 KiB) to account for small overhead around the parameters in the request. If you can share: - Where the 512 KiB limit is coming from in your setup (e.g., Cloud vs. self-hosted, worker type like Docker/Kubernetes/ECS) - An example structure of your parameters …I can tailor more specific guidance (and suggest storage/block patterns that fit your worker/platform).

That is a good point, thank you! I’m wanting to verify the size, as I’m a little suspicious.