Common errors and problems
On this page, you’ll find the explanation and the solution to the common problems that you might get while using ArduinoJson.
Try the ArduinoJson Troubleshooter; it will help you solve your issue quickly.
Beginner gotchas
- Why can’t I use
NULL? - I found a memory leak in the library!
- Why does the output contain garbage?
- Why is the output incomplete?
deserializeJson()succeeds by I cannot read any value
Compilation errors
ambiguous overload for 'operator=' (operand types are 'String' and ...)call of overloaded 'println(...)' is ambiguousDynamicJsonBuffer/StaticJsonBuffer is a class from ArduinoJson 5invalid conversion from 'const char*' to 'char*' [-fpermissive]invalid initialization of reference of type 'String&' from expression of type '...'🆕invalid use of incomplete type 'class InvalidConversion<...>'macro "min" passed 3 arguments, but takes just 2no matching function for call to 'BasicJsonDocument::BasicJsonDocument()'no matching function for call to 'convertFromJson(...)'
(that’s the same page asinvalid initialization of reference of type 'String&' from expression of type '...')no matching function for call to 'convertToJson(...)'no matching function for call to 'makeString(const int&)'request for member 'write' in ..., which is of non-class type 'char*'
Run-time issues
- Why does ArduinoJson return
NotSupported? - I found a memory leak in the library!
- Why is the input modified?
- Why does the output contain garbage?
- Why is the output incomplete?
- The serialized document contains
nullinstead of a string