Template send fails with Invalid parameter: add parameter_name to each variable

TL;DR: When the Cloud API rejects a template send with (#100) Invalid parameter and "Parameter name is missing or empty", check the parameters array. Every text parameter object must include parametername matching the variable name in the approved template, e.g. {"type": "text", "parametername": "customer_name", "text": "John"}.

Template send fails with Invalid parameter: add parameter_name to each variable

Fix

1. When the Cloud API rejects a template send with (#100) Invalid parameter and "Parameter name is missing or empty", check the parameters array. Expected: this specific failure stops.

2. Every text parameter object must include parametername matching the variable name in the approved template, e.g. {"type": "text", "parametername": "customer_name", "text": "John"}. Expected: this specific failure stops.

Details

Sending only {"type": "text", "text": "John"} triggers this exact error. Text values should be plain strings, double-quoted, with no extra nesting. This applies to template sends outside the 24-hour window where every variable must resolve. Context: Stack Overflow #79396912 (best answer, 11 votes): sending a template message fails with "(#100) Invalid parameter", details "Parameter name is missing or empty". The top answer says every object in the parameters array needs a parameter_name matching the template, not just type and text.

When to use

You hit exactly this: Template send fails with Invalid parameter: add parameter_name to each variable in Template.

When not to use

A different error, or the same symptom in a different tool. This page only covers the failure above.

Compatibility

Template.

Stack Overflow #79396912 (best answer, 11 votes): sending a template message fails with "(#100) Invalid parameter", details "Parameter name is missing or empty". The top answer says every object in the parameters array needs a parametername matching the template, not just type and text. Resolved: When the Cloud API rejects a template send with (#100) Invalid parameter and "Parameter name is missing or empty", check the parameters array. Every text parameter object must include parametername matching the variable name in the approved template, e.g. {"type": "text", "parametername": "customername", "text": "John"}. Sending only {"type": "text", "text": "John"} triggers this exact error. Text values should be plain strings, double-quoted, with no extra nesting. This applies to template sends outside the 24-hour window where every variable must resolve.