Create an account

Everything starts at app.stackin.io — sign up and log in. There's no separate "developer" account: the same login is used for the dashboard where you manage companies, keys, and billing.

Before you can create a key, register a company — a company can't be skipped, it's the identity every document is issued under (tax id, address, tax regime). One account can hold multiple companies, each with its own keys and its own credit balance.

From the company's Settings → API key screen, create a key and choose its context: sdk if you're using one of the official client libraries, or api if you're calling the REST API directly with a Bearer token. Context is fixed for the key's whole lifetime and decides which surface it authenticates — an sdk-context key won't work as a raw API Authorization header, and vice versa.

Also choose the key's environment — homologation or production, defaulting to homologation — fixed at creation alongside the context. A company can hold up to 3 keys total, any mix of context and environment. See Environments for how that choice affects every request.

Copy the key immediately after creating it — it's shown once, at creation time, and can't be retrieved again. If it's lost, the fix is to revoke it and create a new one, not to look it up later.

One thing a key alone doesn't unlock: actually issuing a document requires the company's digital certificate (.pfx/.p12) to be uploaded first, since that's what signs the document for the government authorizer. The key can be created and used for read-only calls beforehand, but issuance will fail without the certificate in place.