CBS Assessment API: Brazil's Federal Revenue Service Opens Incremental Queries and DARF Issuance Starting October 2026

New technical documentation changes how tax systems integrate with CBS assessment

On September 14, 2026, the Brazilian Federal Revenue Service published new technical documentation for the Contribution on Goods and Services (CBS) assessment APIs, with the technical documentation now available to developers. The news is relevant for anyone handling tax, accounting, and IT matters, as it changes the way systems will communicate with the Tax Authority during assisted assessment.

What changes in practice

The Federal Revenue Service published on Monday (14) the new technical documentation for the Contribution on Goods and Services (CBS) assessment APIs. The tools will be made available free of charge starting in October and will allow companies and integrated systems to query information related to the new tax. According to the Revenue Service, the update addresses suggestions from accounting professionals, software companies, and taxpayers who handle a high volume of transactions.

Incremental queries: less data, less processing

The main change compared to the previous model lies in the query format. In practice, the API will no longer need to return all information again with every request; under the new system, only the changes recorded since the user's last query will be presented. The Revenue Service states that the model should reduce the volume of data transmitted and provide shorter processing time, lower computational resource consumption, and lighter files for download and storage.

For those already integrating their ERP with the Consumption Taxation Portal, this represents a real simplification in the synchronization routine: fewer redundant calls, lower bandwidth and processing costs, and feeds that are easier to audit internally.

New services: debts, credits, payments, and DARF

Among the planned services are queries for debts, credits, payments, and collections made by the purchaser, as well as the issuance of collection documents. The rollout schedule is gradual:

• Early October 2026: debt query and credit query;
• Early November 2026: payment query and query of collections made by the purchaser;
• Late November 2026: issuance of DARF for Purchaser Collection (RAD) and issuance of DARF for Taxpayer Payment (PCONT).

The new APIs will be made available gradually in the Restricted Production (CBS Pilot) and Beta Production environments, meaning development teams can already start testing the integration before the October rollover.

Why this matters for ERP operators

The CBS assisted assessment is the mechanism through which the Revenue Service calculates debts, credits, and payments based on the tax documents issued by the company, and returns this calculation for verification. The more direct the ERP's integration with these APIs, the less manual rework is needed to download reports, reconcile spreadsheets, and compare figures with accounting records.

It's worth remembering the context: in 2026, assisted assessment still functions as a testing period, with no penalties for any errors identified. But this safety margin has a deadline. This year, assisted assessment does not generate any charges; starting in 2027, with CBS at the full rate, confirming an incorrect assessment means paying the wrong tax or improperly acknowledging a debt. In other words, the period from October to December 2026 is the ideal window to validate whether the data coming out of the ERP matches the data the Revenue Service is calculating via the API.

What to do now

• Map with the IT team which systems currently query or will query the CBS assessment, and plan the migration to the incremental query model;
• Monitor the technical documentation published by the Revenue Service to adapt the use of the new debt, credit, and payment routes according to the October and November schedule;
• Test DARF issuance via RAD and PCONT as soon as the service goes live, avoiding reliance on manual issuance alone;
• Cross-check internally the values returned by the API with the assessment made by the ERP, taking advantage of the fact that 2026 is still an adjustment year without penalties.

Software development companies and taxpayers using system integration should consult the technical documentation and begin planning the necessary adjustments, following the service rollout schedule to ensure proper integration with the new APIs.

This content is informational and does not replace guidance from your accounting team or a tax professional for your company's specific situation.

If your team wants to understand how the CBS assisted assessment connects to the ERP and avoid rework during the October transition, talk to Edoo.