Rate Limits & Quotas

Each Data API key can carry a usage plan set by your environment administrator, made up of:

Throttle — a requests-per-second rate limit with a burst allowance (sliding window).
Quota — a total request allowance per calendar period (DAY, WEEK or MONTH), resetting at the period boundary (UTC).

Keys without a plan are not throttled or quota-limited, but all usage is still metered and visible to your environment administrator.

Response headers

Every successful (and throttled) response includes headers describing where you stand:

Header	Present when	Meaning
`X-RateLimit-Limit`	key has a throttle	Allowed requests per second
`X-RateLimit-Remaining`	key has a throttle	Requests remaining in the current window
`X-Quota-Limit`	key has a quota	Total requests allowed in the current period
`X-Quota-Remaining`	key has a quota	Requests remaining in the current period
`X-Quota-Resets-At`	key has a quota	ISO 8601 timestamp when the period resets
`Retry-After`	throttled `429` only	Seconds to wait before retrying

Watch X-Quota-Remaining in your integration and slow down proactively as it approaches zero.

429 responses

There are two distinct 429 Too Many Requests cases:

Rate limit exceeded (throttle)

You sent requests faster than the key’s per-second allowance. The response includes a Retry-After header (in seconds) and a body with the precise wait in milliseconds:

{
  "message": "Rate limit exceeded. Please slow down your requests.",
  "retryAfterMs": 740
}

Recovery: wait Retry-After seconds (or retryAfterMs) and retry. Throttled requests do not consume quota.

Quota exceeded

The key has used its full allowance for the current period. The body tells you when the period resets:

{
  "message": "Quota of 10,000 requests exceeded. Resets at 2026-08-01T00:00:00.000Z.",
  "resetsAt": "2026-08-01T00:00:00.000Z"
}

Recovery: retrying sooner will not help — wait until resetsAt, or ask your environment administrator about the key’s usage plan.

Worked retry example

A resilient client retries throttled requests with the server-provided delay, and stops when the quota is exhausted:

#!/usr/bin/env bash
# Fetch projects with automatic retry on throttling.
API_KEY="n3_data_xxxxxxxxxxxxxxxxxxxxxxxx"
URL="https://data.n-3.co.uk/data/projects?limit=200"

for attempt in 1 2 3 4 5; do
  response=$(curl -s -w '\n%{http_code}\n%{header_json}' \
    -H "x-api-key: ${API_KEY}" "${URL}")

  status=$(echo "${response}" | sed -n '2p')

  if [ "${status}" = "200" ]; then
    echo "${response}" | sed -n '1p'   # the JSON body
    exit 0
  fi

  if [ "${status}" = "429" ]; then
    retry_after=$(echo "${response}" | sed -n '3,$p' \
      | jq -r '."retry-after"[0] // empty')

    if [ -z "${retry_after}" ]; then
      # No Retry-After header => quota exhausted, not throttled. Do not retry.
      echo "Quota exhausted — wait for the period reset." >&2
      exit 1
    fi

    echo "Throttled — retrying in ${retry_after}s (attempt ${attempt})" >&2
    sleep "${retry_after}"
    continue
  fi

  echo "Request failed with status ${status}" >&2
  exit 1
done

echo "Giving up after 5 attempts" >&2
exit 1

The same pattern in any language: on 429, retry after Retry-After seconds if the header is present; if it is absent, the quota is exhausted — back off until resetsAt.

Checking your status — `GET /data/quota`

GET /data/quota returns your key’s current quota and throttle status. It is the free status check: it never consumes quota, and it requires no scope — any valid Data API key can call it. Poll it as often as you like.

curl "https://data.n-3.co.uk/data/quota" \
  -H "x-api-key: n3_data_xxxxxxxxxxxxxxxxxxxxxxxx"

Response:

{
  "api_key_id": "0b2f6c1e-9a44-4c1d-8f3a-2f9d1c5e7a10",
  "environment_id": "42",
  "scopes": ["data:projects", "data:benchmarks", "data:reports"],
  "quota": {
    "used": 1240,
    "limit": 10000,
    "remaining": 8760,
    "resets_at": "2026-08-01T00:00:00.000Z",
    "period": "MONTH"
  },
  "throttle": {
    "rate_limit_per_second": 10,
    "burst_limit": 20
  }
}

quota and throttle are null when the key has no quota or throttle plan respectively. The scopes array is also the easiest way to confirm exactly what your key can access.

API Documentation

Data API (DAAS)

Analytics

Projects

Reports

Document Studio

Benchmarking

Community

Response headers

429 responses

Worked retry example

Checking your status — `GET /data/quota`

​Response headers

​429 responses

​Worked retry example

​Checking your status — GET /data/quota

Response headers

429 responses

Worked retry example

Checking your status — `GET /data/quota`