**Source URL:** https://limited.veevavault.dev/commercial/vault-sdk/sdk-integrations/tokens/custom-tokens

# Custom Tokens

Custom tokens are defined using `TokenService` and are resolved at runtime. For example, you might create custom logic in a user-defined service to calculate batch size, then pass the batch size value to a `${Custom.batch_size__c}` token. Learn more about [token service](/commercial/vault-sdk/services/token-service/).

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