Request conventions

Localization

Classic Market endpoints commonly accept:

Field	Format	Example
`country`	ISO 3166-1 alpha-2	`US`
`language` or `l`	Steam language name	`english`
`currency`	Steam currency enum	`1`

Currency enum values are Steam implementation details. Responses can contain localized formatted strings even when numeric values are also present.

Pagination

Two pagination conventions are used:

start plus count for legacy render endpoints;
start in a one-element JSON array for structured POST search/listing endpoints.

Structured POST bodies

The newer search and listing endpoints accept a JSON array containing one request object, not a bare object.

[
  {
    "appid": 730,
    "filters": {},
    "accessoryFilters": {},
    "price": { "eCurrency": 1 },
    "sort": 3,
    "direction": 1,
    "start": 0
  }
]

filters selects catalog tags by internal name, accessoryFilters selects applied stickers and charms by display name, and propertyFilters constrains numeric asset properties by inclusive range. See Search filters for the categories, their values, and how they combine.

Headers

Send a normal browser-compatible User-Agent, an accurate Accept value, and Origin: https://steamcommunity.com where the web client does. Do not assume that HTTP 200 means application success; inspect the JSON success value and message.