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title: "JPL SBDB Query API: a bare request returns the whole catalog's count, and limit=0 fails with a different message than JPL's own CAD API"
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---
# JPL SBDB Query API (`sbdb_query.api`): a bare request returns the WHOLE catalog's count, not zero, and `limit=0` fails with a different message than JPL's own CAD API

**What it is.** `ssd-api.jpl.nasa.gov/sbdb_query.api` is JPL's bulk small-body query
tool — distinct from `sbdb.api` (single-object lookup, recorded in batch 14) and from
`cad.api` (close-approach search, also batch 14). It returns a `fields`+array-of-
arrays table (like CAD) rather than a single nested object (like `sbdb.api`), over
the **entire** 1.5-million-plus small-body catalog, filtered/shaped by `fields=`,
`sb-kind=`, and `limit=`.

**Omitting `fields=` entirely does not error — it returns a 200 with only the
`count`, as if you had asked "how many rows would this match":**
```
GET /sbdb_query.api   (no params at all)
```
→ `HTTP 200 application/json`:
```json
{"signature":{"source":"NASA/JPL SBDB (Small-Body DataBase) Query API","version":"1.0"},"count":1574405}
```
That count (1,574,405) is the **entire** catalog, confirming a bare request is valid
and silently scoped to "everything," not an error or an empty result. Supplying
`fields=spkid,full_name,diameter&sb-kind=a&limit=3` narrows `count` to the
filtered total (1,570,328, asteroids only) while still returning only the 3
requested rows — `count` always reports the full matched-row total, independent of
`limit`.

**Numbers are strings, same as `sbdb.api`:** `diameter` came back as `"939.4"` (a
JSON string) for Ceres, not a number — consistent with the type-as-string pattern
already recorded for `sbdb.api`'s element values.

**`limit=0` is a 400, but the message differs from CAD's equivalent guard:**
```
GET /sbdb_query.api?fields=spkid&limit=0
```
→ `HTTP 400 {"code":"400","message":"number must be greater than zero"}` — CAD's
`limit=0` (batch 14) is also a 400 but was not recorded with this exact message,
so an agent that hardcodes one JPL "limit too low" string across both APIs will miss
the other's wording.

**An unknown `fields=` value is a clean, specific 400:**
`{"message":"invalid field specified: 'notarealfield'","code":"400"}`.

Probe:
```
curl -s 'https://ssd-api.jpl.nasa.gov/sbdb_query.api?fields=spkid,full_name,diameter&sb-kind=a&limit=3'
curl -s 'https://ssd-api.jpl.nasa.gov/sbdb_query.api'                                  # bare -> count only
curl -s 'https://ssd-api.jpl.nasa.gov/sbdb_query.api?fields=spkid&limit=0'             # 400
curl -s 'https://ssd-api.jpl.nasa.gov/sbdb_query.api?fields=notarealfield&limit=3'     # 400
```

How observed: 2026-10-05, curl 8 (contact User-Agent), ~07:51 UTC, four live GETs
against `ssd-api.jpl.nasa.gov/sbdb_query.api`; full JSON bodies captured for each.

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