How Spark Vocab stores your progress.

Temporary visitor accounts

When you first use Spark Vocab, Firebase Authentication creates a temporary anonymous account. This lets Spark Vocab enforce the five-check visitor allowance and save progress online without asking for an email address. The temporary account is identified by a Firebase user ID, not by your name.

Registered account information

If you create or sign in to an account, Firebase Authentication stores the identifiers needed to provide access. For email-and-password accounts, Spark Vocab does not receive or store your plain-text password. If you use Google sign-in, Google and Firebase provide basic account information such as your email address and provider identifier. Creating a new account links the temporary session to the new credentials; signing in to an existing account merges temporary browser progress into that account.

Vocabulary progress

Learned words, saved sentences, completed Practice levels and recent sentence-check results are kept in your browser and synchronized to a private Cloud Firestore record associated with your Firebase user ID.

AI sentence checking

When a learner selects Check my sentence, the sentence, target word, part of speech, definition, example, level and any word-specific checking guidance are sent through a protected Firebase function to OpenAI for automated feedback. The OpenAI API key is never sent to the learner’s browser. Spark Vocab sends requests with response storage disabled.

Stripe billing

Spark Vocab uses Stripe to process Plus subscriptions. When you begin checkout, Spark Vocab sends Stripe your account email address, a private Firebase account reference and the plan you selected. Payment-card and billing details are entered directly into Stripe’s hosted checkout and are not stored by Spark Vocab. Spark Vocab stores Stripe customer and subscription identifiers, the selected plan, subscription status, renewal or end date and payment-status events so that Plus access can be provided correctly.

AI allowance records

Spark Vocab stores the number of AI sentence checks used within the relevant allowance period. Visitors receive five checks, registered Free accounts receive 20 checks each calendar month (UTC), and active Plus accounts receive up to 1,000 checks per calendar day (UTC). Short-term rate-limit and reservation records are also stored to prevent simultaneous requests from bypassing these limits.

Safety and local result caching

Submitted sentences are screened for classroom suitability. A returned result is cached in the browser so an identical sentence can be shown again without another AI request. That browser cache is included in the learner’s synchronized progress record. Spark Vocab does not perform a global cross-user sentence-result lookup.

Administrator content

Vocabulary drafts and publication history are available only to Firebase accounts with a server-assigned administrator permission. Published vocabulary content and approved card images are publicly readable so the learning pages can display them.

Your control

Unchecking a learned word removes its saved sentence and Practice history from the current progress record. Plus subscribers can use the Stripe customer portal to view invoices, update payment details and cancel a subscription. Account deletion, data export and longer-term retention controls should be finalized before full commercial release. Learners should not include names, addresses, contact details or other private information in practice sentences.

When you use the Contact form, Spark Vocab processes the name, email address, subject and message you provide so the support team can reply. The form also uses limited technical information to prevent spam and excessive submissions. Contact messages are delivered to support@sparkvocab.com.