Privacy Policy

Effective Date: February 16, 2026 · Last Updated: August 31, 2026

How Proso Handles Your Data

Proso is designed with privacy as a core principle. Page text is extracted locally and leaves your browser only after you ask Proso to read it. Depending on the route you configure, that text goes to the Proso synthesis API and selected TTS provider, directly to a provider under BYOK, or to a synthesis host whose address you entered.

Extension Data (All Users)

  • Text extraction: When you activate Proso on a webpage, the extension extracts text content directly in your browser. Only the text you ask to hear is sent to the synthesis route you selected.
  • API keys: If you use Bring Your Own Key (BYOK), your API keys are cached locally in your browser using browser.storage.local. When you generate audio, your key is forwarded over HTTPS to the Proso server, which uses it for a single API request to your selected TTS provider and immediately discards it. Keys are never persisted, logged, or stored on the server.
  • Audio cache: Generated audio is cached locally in your browser's IndexedDB storage to avoid redundant API calls. This data stays on your device.
  • Settings and preferences: Your playback speed, voice selection, synthesis-host address, and other preferences are stored locally in your browser.
  • Usage telemetry: The public Mozilla Add-ons build does not initialize usage telemetry and has no telemetry destination permission or credential. Its manifest declares the website content necessarily transmitted for synthesis and optional authentication information when you choose BYOK, but it does not transmit interaction events, diagnostics, page URLs, or browsing activity to Proso.

Data Sent to TTS Providers

When you generate audio through a cloud provider, the requested text is sent to the selected provider (OpenAI, ElevenLabs, Groq, or Cartesia), either through Proso’s synthesis API or through the configured BYOK route. When you choose a synthesis host you operate, the text goes only to the exact address stored in your settings. Each destination’s privacy policy and operation governs how it handles that text.

Managed Credit Users (Paid Subscriptions)

If you subscribe to a paid Proso plan and use managed credits (rather than BYOK), the Proso server processes your requests as follows:

  • Text processing: Text you submit for TTS synthesis is sent to the Proso server, which forwards it to the appropriate TTS provider. We do not store the text content after the audio has been generated and delivered.
  • Credit tracking: We track the number of characters processed per billing cycle to manage your credit allocation. This tracking data includes character counts, timestamps, and your account identifier. It does not include the text content itself.
  • Account data: Your email address and subscription status are stored for billing and account management purposes.
  • Data retention: Credit usage data is retained for the duration of your subscription plus 30 days after cancellation. Account data is retained as required for financial record-keeping.

Cookies and Tracking

This website uses zero cookies. There are no tracking scripts, no analytics services, and no third-party advertising on this site.

The public Proso extension collects no browsing or usage-telemetry data. It does not track which websites you visit or send interaction analytics. Page extraction and synthesis begin only after a public control, paragraph action, selection action, or configured shortcut asks Proso to read.

We believe privacy should be the default, not a premium feature. Proso practices what it preaches.

One exception, and only when you ask for it: pressing a subscribe button on the pricing page loads the checkout provider’s script so the payment form can open. Until you press it, no third-party code runs on this site. See Payments below.

Payments

Subscriptions are sold through Paddle, which acts as the merchant of record. Your card details are entered into Paddle’s checkout and are never seen by, sent to, or stored on Proso’s servers.

Paddle tells us only what we need to activate your subscription: the plan you bought, the transaction identifier, and the billing period. On the page you land on after paying, your browser presents the claim secret it minted at checkout; we use the transaction identifier only to find the purchase, never as proof of identity. Support releases a key only after verifying the purchaser through Paddle’s records.

Your Rights

Depending on your jurisdiction, you may have the following rights regarding your personal data:

  • Right to access: Request a copy of the personal data we hold about you.
  • Right to rectification: Request correction of inaccurate personal data.
  • Right to erasure: Request deletion of your personal data ("right to be forgotten").
  • Right to data portability: Request your data in a structured, machine-readable format.
  • Right to object: Object to processing of your personal data for certain purposes.
  • Right to withdraw consent: Withdraw your consent at any time where processing is based on consent.

For BYOK users (free tier): We do not permanently store any personal data about you. Your API keys and preferences are stored locally in your browser. During synthesis requests, your API key is processed ephemerally in server memory (never written to disk, logs, or database) and discarded immediately. To stop all processing, simply remove your API keys from the extension settings.

For managed credit users: Contact us at privacy@proso.com.br to exercise any of these rights. We will respond within 30 days.

Third-Party TTS Providers

Proso integrates with the following third-party text-to-speech providers. When you use these providers (whether via BYOK or managed credits), your text data is subject to their respective privacy policies:

Proso is not responsible for the data practices of third-party providers. We encourage you to review their privacy policies before using their services.

Children's Privacy

Proso is not directed at children under the age of 13. We do not knowingly collect personal information from children. If you believe we have inadvertently collected data from a child, please contact us immediately.

Changes to This Policy

We may update this privacy policy from time to time. Changes will be reflected by updating the "Last Updated" date at the top of this page. Continued use of Proso after changes constitutes acceptance of the updated policy.

Contact

For privacy-related inquiries or to exercise your data rights: