Newsletter Signup API: A Safe Server-Side Pattern
A conceptual server-side signup flow covering validation, token privacy, duplicates and confirmation.
A newsletter form should collect only information needed for the publication. For most subscriptions, an email address is enough; name and language can be optional preferences. A company and job title are not required for an ordinary reader.
A practical way to apply it
A safe integration sends the request from your server, validates the project token, checks the address and applies idempotent duplicate handling. Keep the private token out of browser code. Decide how confirmation works, how retries are recognized and how an unsubscribe remains authoritative.
Before using the pattern
A server should validate the project token, normalize the address, apply idempotent duplicate handling and preserve an existing unsubscribe. Return a clear result for accepted, already subscribed and rejected requests without exposing account data. Keep secrets in server configuration, rate-limit public forms and log only what is needed to diagnose errors.
A worked example
Illustrative pseudocode—not a Cadensy endpoint: POST /your-server/newsletter-signups receives email and language, then your server calls a provider using a secret stored in server configuration. The path and provider are placeholders; do not try this against Cadensy.
Common mistakes to avoid
Validate on the server even when the browser also validates. Return a neutral response when revealing whether an address already exists would expose subscriber status. This pattern is conceptual only: Cadensy has not published an operational newsletter API.