API v1

The API provides access to downloading the free datasets and the datasets you are subscribed to.

Getting data with GET requests

Download as much or as little data as you like through customized URLs made through GET requests. Simply follow these steps:

Authorization

In order to access either the free datasets or the datasets you are subscribed to, you must provide your API key in an Authorization header or as an argument to the apikey parameter.

Get an API key by signing up for Public Data Market for free.

If authorization fails, you will receive an HTTP status error code (401).

Data format

To get data as a JSON array (the default), make a GET request to the following URL, passing your API key to the apikey parameter:

https://publicdatamarket.com/api/v1/{username}/{dataset}?apikey=YOURAPIKEY

{username} and {dataset} are found in the URL that hosts the dataset. For example, the free dataset of contact information of all Hong Kong Access to Information Officersat https://publicdatamarket.com/hkdata/accessgovhk/ can be accessed through the API via the following URL (try it now!):

https://publicdatamarket.com/api/v1/hkdata/accessgovhk?apikey=YOURAPIKEY

To get data in a JSON lines or CSV format, pass jsonlines or csv as the argument to the dataformat parameter, e.g.:

https://publicdatamarket.com/api/v1/{username}/{dataset}?apikey=YOURAPIKEY&dataformat=csv

Limits and pagination

Only up to 100,000 data points are returned at a time. If you want to download less, append &limit= and the desired number to the end of the URL. For example, to download only 5 contact details from the dataset above, use:

https://publicdatamarket.com/api/v1/hkdata/accessgovhk?apikey=YOURAPIKEY&limit=5

To download more than 100,000 rows of data, or simply to facilitate downloading smaller chunks of data, you can make multiple requests, each time starting the downloading further down the dataset, using the offset parameter, e.g. to download the next 5 contacts:

https://publicdatamarket.com/api/v1/hkdata/accessgovhk?apikey=YOURAPIKEY&limit=5&offset=5

Filtering

You can filter the data by adding conditions on columns. For example, to get the details for the Hong Kong Access to Information officers with the email address `enquiry@epd.gov.hk` (there are currently 3, including obsolete details), use the URL parameter email (as that is the name of the column) and the argument eq.enquiry@epd.gov.hk (where eq stands for "equals", followed by a dot, followed by the email address to filter on):

https://publicdatamarket.com/api/v1/hkdata/accessgovhk?apikey=YOURAPIKEY&email=eq.enquiry@epd.gov.hk

The full set of operators available is as follows:

Abbreviation	PostgreSQL equivalent	Meaning
eq	`=`	equals
gt	`>`	greater than
gte	`>=`	greater than or equal
lt	`<`	less than
lte	`<=`	less than or equal
neq	`<>` or `!=`	not equal
like	`LIKE`	LIKE operator (to avoid URL encoding you can use `*` as an alias of the percent sign `%` for the pattern)
ilike	`ILIKE`	ILIKE operator (to avoid URL encoding you can use `*` as an alias of the percent sign `%` for the pattern)
in	`IN`	one of a list of values, e.g. `?a=in.(1,2,3)` – also supports commas in quoted strings like `?a=in.("hi,there","yes,you")`
is	`IS`	checking for exact equality (null,true,false,unknown)
isdistinct	`IS DISTINCT FROM`	not equal, treating `NULL` as a comparable value
not	`NOT`	negates another operator
or	`OR`	logical `OR`
and	`AND`	logical `AND`
all	`ALL`	comparison matches all the values in the list
any	`ANY`	comparison matches any value in the list

Ordering

You can reorder the data using the argument order. It uses a comma-separated list of columns and directions, e.g.

https://publicdatamarket.com/api/v1/hkdata/accessgovhk?apikey=YOURAPIKEY&order=latestdate.desc,department.asc

If no direction is specified then order is ascending by default.