Static Website Landing Page + Mailer API

Hi all,

I am building my landing page from scratch (using a reactjs template). I deployed the site as a static site and trying to configure the "Subscribe" or "Sign up for early access".

I configured Big Mailer (as they have free tier with 1000 contacts), connected my form to send an API request to create contact (access of API key is restricted to create only, no read/update/delete so I'm okay with this API key being public), but getting a CORS error. I tried using "mode: no-cors" but that doesn't work either.

I couldn't find any documentation on Big Mailer site regarding CORS and typically that's a server side change to accept requests from my site (although currently just localhost).

Any thoughts on how to proceed or other email providers that could just collect my subscribers?

For context, here is my code:

    const request: BigMailerRequest = {
      unsubscribe_all: false,
      email: subscriber.email,
      field_values: [
        { name: "FIRST_NAME", string: firstName ?? "" },
        { name: "LAST_NAME", string: lastName ?? "" },
        { name: "CLICKED_SIGN_UP", string: String(siteStorage.clickedSignup) },
        { name: "WATCHED_VIDEO", string: String(siteStorage.clickedWebsiteVideo) },
        { name: "SOURCE", string: subscriber.source },
      ],
    }

    return new Promise((resolve, reject) => {
      fetch(`https://api.bigmailer.io/v1/brands/{omitted}/contacts`, {
        method: "POST",
        mode: "no-cors",
        body: JSON.stringify(request),
        headers: {
          accept: "application/json",
          "content-type": "application/json",
          "X-API-Key": "{omitted}",
        },
      })
        .then(() => {
          resolve()
        })
        .catch((e) => {
          console.log(e, e)
          reject(e)
        })
    })

Thanks,