To prevent memory issues in Edge, message payload size on the Router and Message Processor is
  restricted to 10MB. Exceeding those sizes results in
  a protocol.http.TooBigBody error.
Use the following properties to change the limits on the Router, Message Processor, or both. Both properties have a default value of "10m" corresponding to 10MB:
conf_http_HTTPRequest.body.buffer.limitconf_http_HTTPResponse.body.buffer.limit
To set these properties:
- Open the 
router.propertiesfile ormessage-processor.propertiesfile in an editor. If the file does not exist, create it:vi /opt/apigee/customer/application/router.properties
or:
vi /opt/apigee/customer/application/message-processor.properties
 - Set the properties as desired:
      
conf_http_HTTPRequest.body.buffer.limit=15m conf_http_HTTPResponse.body.buffer.limit=15m
 - Save your changes.
 - Make sure the properties file is owned by the "apigee" user:
chown apigee:apigee /opt/apigee/customer/application/router.properties
or:
chown apigee:apigee /opt/apigee/customer/application/message-processor.properties
 - Restart the Edge component:
      
/opt/apigee/apigee-service/bin/apigee-service edge-router restart
or:
/opt/apigee/apigee-service/bin/apigee-service edge-message-processor restart