Data API Reference

The Request Metrics API returns the real user monitoring data for a website as JSON. One endpoint gives totals for the whole website. The other breaks the same numbers down by URL. The API only reads data, so no request can change your account.

Every metric is the 75th percentile across the page views in your date range. That’s the number the Request Metrics dashboard shows, and it’s the number Google uses to judge Core Web Vitals.

What you need

Every request needs three values.

Account administrators find all three on the Account Settings page. That page also has example links with your IDs and key filled in. Open one to confirm everything works before you write any code.

Warning: Your API key lets anyone read the performance data for every website in your account. The key travels in the URL, so any copy of a request URL carries a live key. Keep those URLs out of shared documents, tickets, screenshots, and logs.

Authentication

Pass your API key as the key query parameter on every request. There’s no header authentication. Request Metrics checks the key against the account in customerId and returns HTTP 401 when the key is missing or belongs to a different account.

Endpoints

Both endpoints live under https://app.requestmetrics.com/api/v1/{customerId}/{applicationId}.

Overall website performance

GET /api/v1/{customerId}/{applicationId}/performance

Returns one object with totals for the website over the date range. It takes the key, p, and device_filter parameters.

curl "https://app.requestmetrics.com/api/v1/{customerId}/{applicationId}/performance?p=7d&key={apiKey}"

{
  "data": {
    "pageLoads": 48213,
    "userCount": 12050,
    "loadP75": 1840,
    "fcp": 1120,
    "lcp": 2240,
    "cls": 0.04,
    "inp": 160,
    "ttfb": 410,
    "rmUrl": "https://app.requestmetrics.com/app/{applicationId}"
  },
  "metadata": {
    "startDate": "2026-10-20T17:04:12.441+00:00",
    "deviceFilter": "overall"
  }
}

Performance by URL

GET /api/v1/{customerId}/{applicationId}/performance/pages

Returns an array with one object per URL or URL group, sorted by page views from most to fewest. It takes every parameter in the next section.

curl "https://app.requestmetrics.com/api/v1/{customerId}/{applicationId}/performance/pages?p=30d&device_filter=mobile&key={apiKey}"

{
  "data": [
    {
      "pageUrl": "https://example.com/pricing",
      "pageLoads": 8120,
      "userCount": 5230,
      "loadP75": 1600,
      "fcp": 980,
      "lcp": 2010,
      "cls": 0.02,
      "inp": 140,
      "ttfb": 360,
      "rmUrl": "https://app.requestmetrics.com/app/{applicationId}/ux/explore/load/{filter}"
    }
  ],
  "metadata": {
    "startDate": "2026-09-27T17:04:12.441+00:00",
    "deviceFilter": "mobile",
    "urlGroupingMode": "ungrouped",
    "currentPage": 1,
    "pageSize": 50,
    "totalPages": 7,
    "totalItems": 312
  }
}

Parameters

Date range

p takes a named range or a custom one.

For a custom range, pass p=c_{start}_{end} with the start and end in Unix epoch seconds. p=c_1730498400_1730584800 is one day. The start has to come before the end. The range can’t reach back more than 90 days or end in the future.

Warning: The API doesn’t reject a date range it can’t use. A misspelled range, or a custom range that breaks one of those rules, returns the last 24 hours with no error. Check metadata.startDate in the response to confirm you got the range you asked for.

Your plan’s data retention limits how far back data goes. A 90d request on a plan that keeps 30 days returns those 30 days.

Device filter

Leave device_filter off to include every device. Set it to mobile or desktop to narrow the results. Any other value counts as all devices.

URL grouping

urlGrouping sets what pageUrl holds on the performance by URL endpoint.

URL Grouping explains how to send custom group names from your website.

Paging

The performance by URL endpoint returns 50 rows at a time unless you set size. Read metadata.totalItems and request each page in turn until you have that many rows. Drive paging from totalItems, because totalPages can count one extra, empty page.

Response fields

Both endpoints return data and metadata. On the overall endpoint, data is one object. On the performance by URL endpoint, data is an array of the same objects, each with a pageUrl.

A metric of -1 means there was no data for it in the date range. Leave it out of averages and charts.

userCount counts the IDs your website passes to RM.identify, or anonymous browser IDs if it doesn’t call it. It’s an estimate, so small changes between date ranges don’t mean much.

Rating the numbers

Request Metrics rates each metric against Google’s thresholds. LCP, INP, and CLS are the three Core Web Vitals.

Errors and rate limits

The rate limit counts requests per website, by customerId and applicationId, and resets every minute. A 429 has an empty body. Wait for the next minute and try again. For a large export, raise size so you need fewer requests.

A valid key with a website ID that has no data returns 200, with pageLoads of 0 and every metric at -1. If every number is empty, check your IDs before you decide the website had no traffic.

Examples

The last week for the whole website

curl "https://app.requestmetrics.com/api/v1/{customerId}/{applicationId}/performance?p=7d&key={apiKey}"

The slowest pages on mobile

Request performance by URL for 30 days with the mobile filter. Then sort the array by lcp or loadP75, skipping any -1 values.

curl "https://app.requestmetrics.com/api/v1/{customerId}/{applicationId}/performance/pages?p=30d&device_filter=mobile&key={apiKey}"

Mobile against desktop

Make the same request twice, once with device_filter=mobile and once with device_filter=desktop, and compare the results.

Every URL for the last 30 days

This JavaScript reads every page of results. It keeps the API key in an environment variable so the key stays out of your source code.

const customerId = "abcdefg";
const applicationId = "1234567";
const key = process.env.RM_API_KEY;

async function getAllPages() {
  const rows = [];
  let page = 1;
  let totalItems = 1;

  while (rows.length < totalItems) {
    const params = new URLSearchParams({ p: "30d", page, size: 100, key });
    const url = `https://app.requestmetrics.com/api/v1/${customerId}/${applicationId}/performance/pages?${params}`;
    const response = await fetch(url);
    if (!response.ok) {
      throw new Error(`Request Metrics returned ${response.status}`);
    }

    const body = await response.json();
    totalItems = body.metadata.totalItems;
    if (body.data.length === 0) break;
    rows.push(...body.data);
    page++;
  }

  return rows;
}

Ask Claude instead

The Request Metrics Claude Skill teaches Claude to make these requests for you. Ask a question in plain language, and Claude pulls the numbers, pages through long lists of URLs, and rates the results.

What the API doesn’t include

The API covers real user performance for your websites. Analytics, errors, API monitoring, sessions, funnels, Lighthouse results, and Chrome UX Report data are only in the Request Metrics app. If you need more in the API, tell us at hello@requestmetrics.com.