Cumulocity IoT - API calls block after a (large?) number of requests in limited time

What product/components do you use and which version/fix level?

Cumulocity API

Are you using a free trial or a product with a customer license?

API deployed as part of our Cumulocity subscriptions (

What are trying to achieve? Please describe in detail.

End to end testing

Do you get any error messages? Please provide a full error message screenshot and log file.

We do not get any errors. At some point API calls just block and wait till the client (calling) OS decides to close the connection

Have you installed latest fixes for the products

We use plane HTTP calls to invoke the cloud deployed Cumulocity API backend

To summarize - our integration tests oftentimes block on an API call to Cumulocity. It always seems to happen after a ‘larger’ number of requests (>1000) in a ‘limited’ time. We do not receive a 427 but the calls just blocks until the OS on the client side closes the connection

Any guidance on how to avoid this would be greatly appreciated.


Peter Coppens

Hi Peter,

can share additional details about the integration test:

  • what kind of requests are talking about?
    • loading information from the Inventory or sending measurements?
    • can you list specific requests
  • how do you execute the requests to Cumulocity?
    • is it via a script?
    • do you use any SDK for sending the requests?
  • what is the tps (transaction per seconds) you see?

Best regards

Hello Christian,

Tx for your quick(!) reaction.

Normally we send these requests through our backend service but we can reproduce the problem using postman

The requests are main inventory calls

Here are a few examples in ‘curl’ form

curl -k -i --raw  "[](" -H "host: [](" -H "accept: */*" -H "user-agent: AHC/2.1"
curl -k -i --raw  "[](" -H "host: [](" -H "accept: */*" -H "user-agent: AHC/2.1"
curl -k -i --raw  "[$filter=name%%20eq%%20d2e20311-dd1e-41eb-bf2b-af3aa393691d]($filter=name%%20eq%%20d2e20311-dd1e-41eb-bf2b-af3aa393691d)" -H "host: [](" -H "accept: */*" -H "user-agent: AHC/2.1"




Anyone any tips or similar experiences wrt to this issue?



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