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Creating Betfair API Certificates with OpenSSL on Windows

This guide walks through generating Betfair API certificates from scratch using OpenSSL on Windows.

Why use certificates?

The certificate proves:

  • The request is coming from a trusted registered client
  • The client owns the private key associated with the uploaded certificate

When you upload a certificate to Betfair:

  • Betfair stores the public certificate
  • You keep the private key locally
  • Requests signed using that key can be validated by Betfair

If someone steals:

  • your username/password → still not enough
  • your app key → still not enough
  • they ALSO need your private key → otherwise authentication fails

Think of authentication like this:

Component Role
Username/password Who you are
App key Which application you are using
Certificate Proof your application is trusted

The certificate is the strongest binding factor between your code and your account.

1. Install OpenSSL

Download the Windows installer

Install:

  • Win64 OpenSSL if using 64-bit Windows
  • Use default installation settings

During installation select "Copy OpenSSL DLLs to: The OpenSSL binaries (/bin) directory"

2. Create a working directory for creating certificates

e.g. "C:\Users\Mitch\Documents\Betfair_Certs"

3. Open OpenSSL Installation

  • Open Win64 OpenSSL Command Prompt from the Windows Search Bar
  • Change the working directory using the command "cd" - e.g. "cd C:\Users\Mitch\Documents\Betfair_Certs"

4. Generate Private Key

Run:

openssl genrsa -out client-2048.key 2048

This creates:

client-2048.key

This is your private certificate key.

5. Generate Certificate Signing Request (CSR)

Run:

openssl req -new -key client-2048.key -out client-2048.csr

You will be prompted for certificate information.

Example:

Country Name (2 letter code) [AU]:AU
State or Province Name (full name) []:Victoria
Locality Name (eg, city) []:Melbourne
Organization Name (eg, company) []:Personal
Organizational Unit Name (eg, section) []:API
Common Name (e.g. server FQDN or YOUR name) []:Betfair API
Email Address []:your@email.com

For these fields simply press Enter:

A challenge password []:
An optional company name []:

This creates:

client-2048.csr

For anything regarding organization, simply enter '.' and it will be blank

6. Generate Self-Signed Certificate

Run:

openssl x509 -req -days 365 -in client-2048.csr -signkey client-2048.key -out client-2048.crt

This creates:

client-2048.crt

You should now have:

client-2048.key
client-2048.csr
client-2048.crt

The .csr file is no longer needed after the certificate is created.

7. Create the .pem file

In any text-editor, combine the text from the client-2048.key and client-2048.crt files into a new file. Save this file as 'client-2048.pem'

After saving, check that the file is client-2048.pem and NOT client-2048.pem.txt

8. Upload Certificate to Betfair

Login to Betfair.

Navigate to https://myaccount.betfair.com.au/accountdetails/mysecurity?showAPI=1

Upload the below file to Automated Betting Program Access

client-2048.crt

Do NOT upload the .key file.

9. Using Certificates in Python (betfairlightweight)

Example:

from betfairlightweight import APIClient
import pprint

certs_path = 'C:\Users\Mitch\Documents\Betfair_Certs'

trading = APIClient(
    username='YOUR_USERNAME',
    password='YOUR_PASSWORD',
    app_key='YOUR_APP_KEY',
    certs=certs_path
)

login_response = trading.login()
pprint.pprint(vars(login_response))

Folder structure example:

C:\Users\Mitch\Documents\Betfair_Certs\
    client-2048.pem

10. Notes

  • Betfair Australia users do NOT require a separate developer account
  • Certificates are required for non-interactive login
  • Keep your .key file private
  • Never share the private key publicly

Further Support

Australian customers can email us for support at automation@betfair.com.au