> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# Lerian SPI API contract changes

> Four API contract changes shipped in Lerian SPI 1.0.0: the idempotency header, two lookups on POST, MED cases on DICT, and a separate direct-participant route.

<Badge stroke icon="calendar-days" iconType="regular">September 30, 2026</Badge> <Badge stroke icon="file-code" iconType="regular">Product update</Badge> <Badge color="purple" size="lg" stroke icon="eye" iconType="regular">Action required</Badge>

## Affects

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Teams that integrated with the Lerian SPI API before these changes shipped.

## What changed

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Lerian SPI 1.0.0, released on September 29, 2026, carries these changes.

**The idempotency header changed to `X-Idempotency`.** The SPI, DICT, BR Code, and Core APIs stopped reading `Idempotency-Key` and started to read the idempotency key from `X-Idempotency`. A request that carried only `Idempotency-Key` was then refused like a request with no key.

**Two lookups moved to `POST`.** The received Pix list moved from `GET /api/v1/spi/pix` to `POST /api/v1/spi/pix`, and its `cpf` and `cnpj` filters moved into the JSON request body. Person statistics moved from `GET /api/v1/dict/persons/{taxId}/statistics` to `POST /api/v1/dict/persons/statistics`, with `taxId` in the JSON request body.

**The Core MED case routes were removed.** The eight routes under `/api/v1/core/med` were removed.

**The direct participant moved to its own route.** `POST /api/v1/core/participants/` stopped accepting a direct participant, and direct-participant registration moved to the administrative route `POST /api/v1/core/participants/direct`.

## Impact

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**Classification: Action required.** A client that still sends `Idempotency-Key`, calls one of the two `GET` lookups, calls a Core MED route, or sends a direct participant to `POST /api/v1/core/participants/` receives an error.

## What you need to do

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* Send the idempotency key in `X-Idempotency`.
* Call the received Pix list with `POST`, with `cpf` and `cnpj` in the JSON body and the other filters still in the query.
* Call person statistics with `POST`, with `taxId` in the JSON body.
* Ask an authorized administrator to register a direct participant on `POST /api/v1/core/participants/direct`; `POST /api/v1/core/participants/` accepts an indirect participant only.
* Handle MED cases through the DICT API.

## Resources

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* [What is Lerian SPI?](/en/rails/spi/what-is-lerian-spi)
* [How Lerian SPI works](/en/rails/spi/how-spi-works)
* [SPI error list](/en/reference/rails/spi/spi-error-list)


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