# /iso/ics

`POST /api/iso/ics`

Price: 5 credits

Browse the International Classification for Standards, the three-level subject taxonomy ISO, IEC and the national bodies index standards under. Returns nodes with the code, the English and French titles, the scope note where one exists, the depth, the parent code and the direct child codes, filtered by explicit code, by parent, by depth or by a substring of the title and scope.

## How to use it

Walk the tree with `parent`: no filters returns the whole classification, `level` 1 returns the forty top-level fields, and `parent` set to a code returns its direct children. The codes are the same ones /iec/publications/search takes in `ics_codes`, so this is how to turn a subject into a code an electrotechnical catalogue query can filter on. Scope notes exist on a minority of nodes and say what a field excludes and where that material lives instead, which is often what disambiguates two similar titles. ISO republishes the classification rarely rather than continuously, so treat it as a stable vocabulary.

## Parameters

- `access-token` (string, required)

## Request body

- `timeout` (integer) — Max scrapping execution timeout (in seconds) (default: 300; min: 20; max: 1500)
- `codes` (array, nullable) — Specific ICS codes to return, at any of the three levels (examples: ["03"], ["03.120","35.030"], ["03.120.10"])
- `parent` (string, nullable) — Return the direct children of this ICS code (examples: "03", "03.120"; minLength: 1)
- `level` (integer, nullable) — Restrict to one depth of the tree: 1 field, 2 group, 3 subgroup (min: 1; max: 3)
- `query` (string, nullable) — Case-insensitive substring matched against the English title and scope note (examples: "quality", "welding"; minLength: 1)
- `count` (integer, required) — Max number of results to return (min: 1; max: 1500)

## Response

### 200 — Successful Response

- `@type` (string) (default: "IsoIcsNode")
- `code` (string, required)
- `node_title` (string, nullable)
- `title_fr` (string, nullable)
- `scope` (string, nullable)
- `scope_fr` (string, nullable)
- `level` (integer, nullable)
- `parent` (string, nullable)
- `children` (array) (default: [])
- `url` (string, nullable)

## Errors

### 422 — Validation Error

A code is not a valid ICS code, or level is not deeper than parent

What to do: Check the fields against this schema. A URN with the wrong prefix is the most common cause.

- `detail` (array)
  - `loc` (array, required)
  - `msg` (string, required)
  - `type` (string, required)
  - `input` (any)
  - `ctx` (object)

### 408

The request ran past its time limit

What to do: Raise `timeout` in the request body, up to the maximum this endpoint documents. Lowering `count` or turning off the `with_*` flags also helps, because less work finishes sooner.

### 412

No ICS node matched the filters

What to do: Retrying will not help: either the entity does not exist, or the input points at a different one.

### 429

Too many requests: a rate limit or a usage window is exhausted

What to do: When the response carries an X-Retry-After header, wait that many seconds and retry: the same number is in the body as `detail.retry_after`, and the limit clears once that window passes. The message in the body names the limit that was hit.

### 500

Something broke on our side

What to do: Retrying will not help. If it keeps happening, send us the X-Request-ID from the response headers.

### 529

Rate limit reached, or the endpoint is overloaded

What to do: Wait at least 30 seconds, then retry.

## Response envelope

Success: Array of objects (may be empty if no results)

Error: Error may coexist with partial results if it occurs mid-execution. Check X-Error header and status code.

Every response carries these headers:

- `X-Error` — Error message text (present only on error)
- `X-Request-ID` — Unique request identifier
- `X-Execution-Time` — Execution time in seconds
- `X-Result-Count` — How many records the body carries. 0 means an empty result, which is a normal answer and not by itself an error. A non-zero count can come back together with X-Error when the failure happened partway through — read this header and X-Error independently.
- `X-Total-Available-Results` — How many records exist for this query, when the endpoint can say. On a `dry_run` request this is the answer and the body is empty. It saturates: the endpoint's documented maximum means 'at least that many', any smaller number is exact.
- `X-Warning` — Present when the request body carried keys this endpoint does not document. They were ignored, so any filter you meant to apply through them did not apply. Check the spelling against this schema and retry.
- `X-Retry-After` — Seconds to wait before retrying. Present only on 429.