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Connect without authentication

PubChem’s web services take no credentials, so there is nothing to obtain from NCBI. Create the connection and StackOne starts calling PubChem straight away.

1

Create the connection

Choose the No Authentication option and create the connection in StackOne Hub. There are no fields to fill in.

2

Know the limits

PubChem limits requests to 5 per second per IP address and throttles or blocks heavy use with a 503 error.

  • The Entrez actions call NCBI’s E-utilities, which allow 3 requests per second per IP address without an API key and 10 with one. To use your own key, create the connection with the NCBI API Key option instead.
  • PubChem data licences vary by contributing source. Annotations carry the licence of each source in LicenseNote and LicenseURL.
  • When you publish results that use PubChem, cite: Kim S, Chen J, Cheng T, et al. PubChem 2025 update. Nucleic Acids Res. 2025;53(D1):D1516-D1525. doi:10.1093/nar/gkae1059. Cite a single record by its URL, for example https://pubchem.ncbi.nlm.nih.gov/compound/2244.

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Linking the Account from the Hub

1

Navigate to the Hub

Use one of the three Linking Account Methods to access the Hub.
2

Connect

  • Click Connect
  • If applicable, the provider will redirect you to a sign-in or authorization page. Complete the provider’s authorization flow.
  • Once authorization is successful, you will see a confirmation popup

If the account linking is successful, you will see the newly linked account on your Accounts page.