Failed to serialize source for type root name – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.14-8.9

Briefly, this error occurs when Elasticsearch fails to convert a document into JSON format before indexing it. This could be due to incorrect data types or malformed data. To resolve this issue, you can validate your data before indexing to ensure it matches the mapping. Also, check for any special characters that might be causing the serialization to fail. Lastly, ensure that your Elasticsearch version supports the data types you are using.

This guide will help you check for common problems that cause the log ” failed to serialize source for type [” + + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index, source.

Log Context

Log “failed to serialize source for type [” + + “]” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 public CompressedXContent toCompressedXContent() {
 try {
 return new CompressedXContent(this);
 } catch (Exception e) {
 throw new ElasticsearchGenerationException("failed to serialize source for type [" + + "]"; e);
 }  /**
 * Returns the root object for the current mapping


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