Usage

mudab — a CLI for the MUDAB (Meeresumweltdatenbank) API. No API key needed.

mudab [global options] <command> [command options]

Each command lists one dataset and prints a JSON array of rows to stdout.

Global options

Option	Description
`--base-url <url>`	API base URL (default the canonical `geoportal.bafg.de` MUDAB base)
`--timeout <ms>`	time limit per request in ms, whole response included (0 = no timeout; at most 2147483647)
`--user-agent <ua>`	User-Agent header value
`--max-retries <n>`	retries for transient 429/503 responses
`--max-response-bytes <n>`	cap the response body size in bytes (0 = unlimited; default 100 MiB)
`--compact`	print JSON on a single line (for piping to `jq`)
`-V, --version` / `-h, --help`	version / help

Paging options (every list command)

Option	Description
`--from <n>`	skip this many rows (`range.from`, default 0)
`--count <n>`	max rows to return (default 100)
`--all`	return the whole table (omit the range — can be very large)

No filter or sort options. The API’s OpenAPI spec advertises filter and orderby on every endpoint, but the live server ignores both (a filter that should match nothing still returns the full page — verified). Exposing them would be a filter that does not filter, so this CLI omits them. Filter and sort client-side, e.g. with jq on --compact output.

Commands

Command	Dataset
`mudab stations`	measurement stations (`STATION_SMALL`)
`mudab project-stations`	project / monitoring-programme stations (`PROJECTSTATION_SMALL`)
`mudab parameters [--compartment biologie\\|biota\\|wasser\\|sediment]`	measured parameters (`MV_PARAMETER`, or a compartment-specific endpoint)
`mudab measurements`	individual station measurements (`MV_STATION_MSMNT`) — a very large table
`mudab plc-stations`	HELCOM PLC river-load stations (`V_PLC_STATION`)
`mudab plc-parameters`	parameters measured at PLC stations (`V_GEMESSENE_PARA_PLC`)
`mudab plc-measurements`	measured values at PLC stations (`V_MESSWERTE_PLC`)
`mudab compartments`	print the compartment (`COMPT_DS`) code table — offline, no request

Examples

# First 5 measurement stations, pretty-printed
mudab stations --count 5

# All water parameters, filtered to a substance with jq
mudab parameters --compartment wasser --all --compact \
  | jq '[.[] | select(.PARAM_NAME | test("mercury";"i"))]'

# Look at a few measurement rows, then take the whole table once and filter it
mudab measurements --from 0 --count 5 --compact
mudab measurements --all --compact | jq '[.[] | select(.STATNAME_ST=="OMMVZBA15")] | length'

# Phosphorus river loads for Mecklenburg (LAND_CD "MV")
mudab plc-measurements --all --compact \
  | jq '[.[] | select(.NAME=="Ptot" and .LAND_CD=="MV") | {STATION_NAME, PERIOD_NAME, VALUE, VAL_UNIT}]'

Exit codes

Code	Meaning
`0`	success (help/version included); an empty result also exits 0
`1`	API/logical error, or a catch-all
`2`	usage error (bad flags, unknown command, `--all` with `--from/--count`)
`4`	HTTP 404
`6`	network / transport failure (DNS, connection, timeout, response size-cap)

Notes

measurements is the largest table. On 2026-09-15 --all returned ~187,000 rows, ~42 MB, in about 10 s, under the default 100 MiB --max-response-bytes. The server cannot filter, so any selection needs the whole table: fetch it once and filter the result. If it outgrows the cap (exit 6), raise --max-response-bytes.
A range always sends from. The server answers a count-only range with an HTTP 500, so the CLI always includes from (default 0).