Failed to parse request – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch is unable to understand the request sent to it due to incorrect syntax, missing parameters, or invalid data types. This could be due to a malformed JSON, incorrect query DSL, or incompatible data types. To resolve this issue, you should first validate your JSON or query DSL syntax. If the syntax is correct, check the data types of the fields in your request. Ensure that the request parameters match the expected parameters in terms of both name and data type.

This guide will help you check for common problems that cause the log ” failed to parse request ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: rest, request.

Log Context

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

 try {
 XContentBuilder xContentBuilder = XContentBuilder.builder(result.v1().xContent()).map(transformedSource);
 filteredBytes = BytesReference.bytes(xContentBuilder);
 } catch (IOException e) {
 throw new ElasticsearchException("failed to parse request"; e);
 return filteredBytes;


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