Concepts

{
  "type": "https://developers.ledenboek.nl/errors/insufficient_scope",
  "title": "Insufficient permissions",
  "status": 403,
  "detail": "This key lacks the permission leden:schrijven. An administrator can create a key with that permission.",
  "instance": "/v2/members"
}

# -i shows the status line and headers; errors come as application/problem+json
curl -i https://api.ledenboek.nl/v2/members \
  -H "Authorization: Bearer $LEDENBOEK_API_KEY"

const response = await fetch("https://api.ledenboek.nl/v2/members", { headers });

if (!response.ok) {
  const problem = await response.json(); // application/problem+json
  // problem.type is stable; branch on it, not on the title
  if (problem.type.endsWith("/insufficient_scope")) {
    // ask an administrator for a key with the right scope
  }
  throw new Error(`${problem.status} ${problem.title}: ${problem.detail ?? ""}`);
}

<?php
$body = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);

if ($status >= 400) {
    $problem = json_decode($body, true); // application/problem+json
    $code = basename($problem["type"]);  // for example "insufficient_scope"
    throw new RuntimeException("{$problem["status"]} {$code}: " . ($problem["detail"] ?? $problem["title"]));
}

response = session.get("https://api.ledenboek.nl/v2/members")

if not response.ok:
    problem = response.json()  # application/problem+json
    code = problem["type"].rsplit("/", 1)[-1]  # for example "insufficient_scope"
    for error in problem.get("errors", []):  # only for validation_failed
        print(error["field"], error["message"])
    raise RuntimeError(f"{problem['status']} {code}: {problem.get('detail', problem['title'])}")

curl "https://api.ledenboek.nl/v2/members?updated_since=2026-10-01T00:00:00Z&limit=100" \
  -H "Authorization: Bearer $LEDENBOEK_API_KEY"

// Remember when this run started; that is the next run's updated_since.
const startedAt = new Date().toISOString();
let cursor = null;

do {
  const url = new URL("https://api.ledenboek.nl/v2/members");
  url.searchParams.set("updated_since", lastSync);
  url.searchParams.set("limit", "100");
  if (cursor) url.searchParams.set("starting_after", cursor);

  const page = await (await fetch(url, { headers })).json();
  for (const member of page.data) await upsert(member);
  cursor = page.has_more ? page.next_cursor : null;
} while (cursor);

lastSync = startedAt;

<?php
// Remember when this run started; that is the next run's updated_since.
$startedAt = gmdate("Y-m-d\TH:i:s\Z");
$cursor = null;

do {
    $query = http_build_query(array_filter([
        "updated_since" => $lastSync,
        "limit" => 100,
        "starting_after" => $cursor,
    ]));
    $page = getJson("https://api.ledenboek.nl/v2/members?" . $query);
    foreach ($page["data"] as $member) {
        upsert($member);
    }
    $cursor = $page["has_more"] ? $page["next_cursor"] : null;
} while ($cursor !== null);

$lastSync = $startedAt;

from datetime import datetime, timezone

# Remember when this run started; that is the next run's updated_since.
started_at = datetime.now(timezone.utc).isoformat(timespec="seconds").replace("+00:00", "Z")
cursor = None

while True:
    params = {"updated_since": last_sync, "limit": 100}
    if cursor:
        params["starting_after"] = cursor
    page = session.get("https://api.ledenboek.nl/v2/members", params=params).json()
    for member in page["data"]:
        upsert(member)
    if not page["has_more"]:
        break
    cursor = page["next_cursor"]

last_sync = started_at

# The headers show how much room is left in this minute
curl -s -D - -o /dev/null https://api.ledenboek.nl/v2/organization \
  -H "Authorization: Bearer $LEDENBOEK_API_KEY" | grep -i ratelimit

async function request(url, options, attempt = 0) {
  const response = await fetch(url, options);
  if (response.status === 429 && attempt < 3) {
    const seconds = Number(response.headers.get("Retry-After") ?? 1);
    await new Promise((resolve) => setTimeout(resolve, seconds * 1000));
    return request(url, options, attempt + 1);
  }
  return response;
}

<?php
function request(string $url, array $headers, int $attempt = 0): array {
    $ch = curl_init($url);
    $retryAfter = 1;
    curl_setopt_array($ch, [
        CURLOPT_HTTPHEADER => $headers,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HEADERFUNCTION => function ($ch, $line) use (&$retryAfter) {
            if (stripos($line, "Retry-After:") === 0) {
                $retryAfter = (int) trim(substr($line, 12));
            }
            return strlen($line);
        },
    ]);
    $body = curl_exec($ch);
    if (curl_getinfo($ch, CURLINFO_RESPONSE_CODE) === 429 && $attempt < 3) {
        sleep($retryAfter);
        return request($url, $headers, $attempt + 1);
    }
    return json_decode($body, true);
}

import time

def request(url, attempt=0, **kwargs):
    response = session.get(url, **kwargs)
    if response.status_code == 429 and attempt < 3:
        time.sleep(int(response.headers.get("Retry-After", "1")))
        return request(url, attempt + 1, **kwargs)
    return response