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API Query Syntax

Table of contents

  1. Syntax Overview
  2. Example API Call
    1. Operators
    2. Modifiers
  3. Detailed examples

Syntax Overview

REST collections provide filter, skip, limit and sort support.

  • The field in the message is used as the query parameter
    • Syntax: field=[modifiers][operator]match-string
  • When multiple query parameters are supplied these are combined with AND
  • When the same query parameter is supplied multiple times, these are combined with OR

Example API Call

GET /api/v1/messages?confirmed=>0&type=broadcast&topic=t1&topic=t2&context=@someprefix&sort=sequence&descending&skip=100&limit=50

This states:

  • Filter on confirmed greater than 0
  • Filter on type exactly equal to broadcast
  • Filter on topic exactly equal to t1 or t2
  • Filter on context containing the case-sensitive string someprefix
  • Sort on sequence in descending order
  • Paginate with limit of 50 and skip of 100 (e.g. get page 3, with 50/page)

Table of filter operations, which must be the first character of the query string (after the = in the above URL path example)


Operators are a type of comparison operation to perform against the match string.

Operator Description
= Equal
(none) Equal (shortcut)
@ Containing
^ Starts with
$ Ends with
<< Less than
< Less than (shortcut)
<= Less than or equal
>> Greater than
> Greater than (shortcut)
>= Greater than or equal

Shortcuts are only safe to use when your match string starts with a-z, A-Z, 0-9, - or _.


Modifiers can appear before the operator, to change its behavior.

Modifier Description
! Not - negates the match
: Case insensitive
? Treat empty match string as null

Detailed examples

Example Description
cat Equals “cat”
=cat Equals “cat” (same)
!=cat Not equal to “cat”
:=cat Equal to “CAT”, “cat”, “CaT etc.
!:cat Not equal to “CAT”, “cat”, “CaT etc.
=!cat Equal to “!cat” (! is after operator)
^cats/ Starts with “cats/”
$_cat Ends with with “_cat”
!:^cats/ Does not start with “cats/”, “CATs/” etc.
!$-cat Does not end with “-cat”
?= Is null
!?= Is not null