Failed to convert source to a json string – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch is unable to convert the provided data source into a JSON string. This could be due to incorrect data format, invalid characters, or a malformed JSON structure. To resolve this issue, you can: 1) Validate your JSON structure using a JSON validator tool. 2) Check for any invalid or non-JSON compliant characters in your data source. 3) Ensure that your data source is in the correct format that Elasticsearch expects. 4) If you’re using a programming language to generate the JSON, ensure the serialization process is working correctly.

This guide will help you check for common problems that cause the log ” failed to convert source to a json string ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: search, source.

Log Context

Log “failed to convert source to a json string” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 return null;
 try {
 return XContentHelper.convertToJson(getSourceRef(); false);
 } catch (IOException e) {
 throw new ElasticsearchParseException("failed to convert source to a json string");
 }  /**
 * The source of the document as a map (can be {@code null}).


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