IBM i & SQL Tips #6: Calling REST APIs and Parsing JSON Responses with SQL

I want to share with you a particularly useful article by Massimo Duca in the IBM i & SQL Tips series. In this sixth installment, he shows how to use HTTP functions and JSON capabilities in SQL on DB2 for i to call external REST APIs and process their responses directly in SQL.

🔗 IBM i SQL Tips #6 – Calling REST APIs and Parsing the Response with SQL

What’s inside the article

Here are some of the key topics covered:

• How to perform HTTP requests from DB2 for i SQL to REST APIs (e.g. GET, POST)
• How to handle authentication and headers if needed by the API
• How to receive JSON responses and use SQL functions to parse the JSON: extract specific values, convert JSON arrays into tabular data, transform response data for further querying
• Practical SQL example queries: integrating HTTP → JSON → SQL operations (using JOINs, filters, transformations)
• Awareness of common pitfalls: inconsistent JSON formats, HTTP errors, timeouts, response size limits, DB2 for i constraints

Why this matters

• It lets you bridge IBM i / DB2 with external web services via REST without needing external scripting or middleware.
• Great for embedding dynamic data from external services directly into your SQL-based workflows for IBM i.
• Helps with maintainability: instead of exporting / transforming / importing data elsewhere, you can do much of the work inside SQL where you already manage data.

Thanks Massimo for your great job,