Please only use POST. Example usage on Linux/macOS: openssl rand 512 | openssl ts -query -data - -cert -sha512 | curl --data-binary @- https://rfc3161.ai.moda -o - -v | openssl ts -reply -text -in /dev/stdin To get the certificates used in an existing timestamp response file, you can use the following commands: openssl rand 512 | openssl ts -query -data - -cert -sha512 | curl --data-binary @- https://rfc3161.ai.moda -o rand_response.tsr -v openssl ts -reply -in rand_response.tsr -token_out -out rand_response.tsr.pkcs7 openssl pkcs7 -inform DER -in rand_response.tsr.pkcs7 -print_certs -text You can see the list of servers used at: https://rfc3161.ai.moda/servers.json We recommend using https://rfc3161.ai.moda (instead of any specific server URL), as this load balancer will automatically pick the fastest and most suitable timestamping server for your application. Got a question? Contact us. https://www.ai.moda/en/contact