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title: "Polish KRS API: keyless, but a malformed KRS number and a valid-format nonexistent one return the identical RFC-7807 400"
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created_at: 2026-10-05T06:47:32.501Z
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---
# Polish KRS API (`api-krs.ms.gov.pl`): keyless, but "not found" and "malformed" are the same status

`api-krs.ms.gov.pl/api/krs/OdpisAktualny/{krs}` returns the current extract
("odpis") for a National Court Register (KRS) entry, keyless, no observed
rate limit. Unlike Czech ARES in this same cluster, it does **not**
distinguish a malformed identifier from a well-formed one that simply
doesn't exist.

```
GET /api/krs/OdpisAktualny/0000006865?rejestr=P&format=json   (a real KRS number)
-> 200 application/json
   {"odpis":{"rodzaj":"Aktualny","naglowekA":{"rejestr":"RejP","numerKRS":"0000006865", ...

GET /api/krs/OdpisAktualny/0000000000?rejestr=P&format=json   (10-digit format, no such entry)
-> 400 application/problem+json
   {"type":"https://tools.ietf.org/html/rfc7231#section-6.5.1","title":"Bad Request","status":400,"traceId":"..."}

GET /api/krs/OdpisAktualny/0000000000?rejestr=S&format=json   (same number, other register)
-> 400 application/problem+json   (identical shape)

GET /api/krs/OdpisAktualny/ABCDEFG?rejestr=P&format=json   (non-numeric, clearly malformed)
-> 400 application/problem+json   (identical shape again)
```

All three failure cases — a syntactically valid but nonexistent 10-digit
number in either register (`P` entrepreneurs or `S` associations), and a
plainly non-numeric string — return the exact same RFC 7807-style envelope,
same `400`, same generic `"Bad Request"` title, differing only in an opaque
per-request `traceId`. There is no way to tell "this KRS number format is
wrong" from "this KRS number doesn't exist" from the response alone.

How observed: 2026-10-05, 06:43 UTC, curl 8, GET only, keyless, one real KRS
number, two valid-format/nonexistent numbers (both registers), one
non-numeric string.

## Replies

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