Terms of Use

1. Who we are

stackin is operated by Fernando Celmer, CNPJ 68.849.750/0001-76, in Florianópolis, Brazil. It is a platform for companies to issue Brazilian electronic invoices (NF-e and NFS-e), through the web dashboard, the API, or a connected application. By creating an account you agree to these terms.

2. Who can use it

The account is meant for a company, represented by someone over 18 with authority to contract on its behalf. Issuing invoices requires a properly registered company and a valid digital certificate.

3. Your account

You are responsible for keeping your password safe and for everything that happens in your account. One account can manage more than one company, and each company can have more than one user. Tell us immediately if you suspect unauthorized use.

4. Plans, credits and billing

You pay per authorized document. The current amounts are the ones shown on the pricing page.

• Credit is prepaid balance: R$ 1.00 of credit equals R$ 1.00, and how many invoices it covers depends on your plan's per-invoice price.
• On monthly plans, invoices inside the franchise spend no balance; beyond it, each invoice takes the overage from your balance.
• Without enough balance, issuance is refused — there is no later charge and no overage invoice.
• Only an authorized document is billed. An invoice the authorizer rejects spends no balance, and cancelling, looking up, downloading the PDF, correcting and manifesting are free.
• Issuing in the sandbox never spends balance.
• Purchased credits do not expire and cannot be converted back into money.
• You can change plans at any time, with no lock-in. The change applies from confirmation and does not generate a pro-rata refund of the period already paid.

5. Right of withdrawal

Purchases made online can be undone within seven calendar days, under article 49 of the Brazilian Consumer Code, where the buyer is a consumer. Write to support@stackin.io within that window. We refund the unused portion; credits already spent on authorized issuances are not refundable, because the service was delivered.

6. Digital certificate

By uploading your company's certificate .pfx you authorize stackin to use it solely to sign the invoices you issue through the platform. It is stored encrypted — see the Privacy Policy.

• You are responsible for keeping the certificate valid and the password correct.
• You can remove the certificate at any time — issuance stops working until a new one is uploaded.

7. Connected applications

You can authorize a third-party application — such as the ChatGPT plugin — to act on behalf of your company, through OAuth and within a limited scope. Actions taken by an application you authorized are yours for every purpose, billing included. Review the scopes before authorizing, and revoke access when you no longer need it.

8. Sandbox

The sandbox exists for you to test the integration. Invoices issued there carry no fiscal or legal value, do not work as documents, and may be discarded by the tax authorities at any time.

9. Responsibility for fiscal data

The data in the invoices — recipient, items, amounts, taxes and classifications — is the responsibility of whoever issues them. stackin transmits what was informed to the competent authority and returns its answer; we do not validate whether the content is fiscally correct, we are not your accountant, and we do not provide tax advice.

10. Acceptable use

Do not use the platform to issue false or simulated documents, defraud others, work around technical limits, test the security of the service without authorization, or resell access without an agreement with us. We may suspend or close an account that breaches this section, that is in arrears, or when suspension is needed to contain a security risk — with prior notice whenever possible.

11. Availability

We do our best to keep the service available, but we do not guarantee uninterrupted operation. Issuance also depends on the availability of the tax authorities' systems, outside our control. We may perform maintenance and technical changes, announcing them when they matter.

12. Limitation of liability

To the fullest extent the law allows, we are not liable for lost profits, lost opportunity or indirect damages, nor for fines and assessments arising from data you provided. Our total liability in any case is limited to what you paid for the service in the twelve months before the event. Nothing here removes rights the law grants to consumers.

13. Closing your account

You can close your account at any time on the My account page. Invoices already issued remain — they are fiscal records the law requires us to keep, even after closing. Unused credit balance is not refunded when you close the account yourself, except under the right of withdrawal.

14. Changes to these terms

We may update these terms as the product evolves. The date at the top marks the last revision, and relevant changes are announced in the platform before they take effect. Continuing to use the service after that means accepting the new version.

15. Governing law and venue

These terms are governed by Brazilian law. The courts of Florianópolis, Santa Catarina, are elected, without prejudice to a consumer's right to sue in their own domicile.