Valuation data API

Try it without an account

These endpoints need no key. They carry a subset of the ticker universe and a handful of period-end snapshots rather than the full history — enough to write and test code against.

https://siblisresearch.com/api/v1/indices
https://siblisresearch.com/api/v1/NDX/pe-trailing
https://siblisresearch.com/api/v1/UKX/pe-trailing
https://siblisresearch.com/api/v1/DAX/pe-forward
https://siblisresearch.com/api/v1/N225/cape

/indices lists the tickers the free tier carries and /dates lists exactly which dates it returns. The response shape is identical to the subscriber API, so code written against the free tier keeps working when a key is added.

Base URL

All subscriber calls go to:

https://siblisresearch.com/data-api/v1/

Replace the path after /v1/ to reach a different endpoint — /v1/indices, or /v1/NDX/cape.

The direct endpoint at siblisresearch.supabase.co/functions/v1/data-api/v1/ continues to work and returns exactly the same responses, so existing code needs no change. The address above is the one to use in anything new: it is ours, so the backend can move without breaking your code.

Authentication

Your API key is issued on subscription. It starts with sib_ followed by 16 lowercase hex characters. Keep it secret: anyone holding it can spend your daily quota.

Pass it as a header, which is the right choice for scripts and anything running in production:

x-api-key: sib_xxxxxxxxxxxxxxxx

Or as a query parameter, which is convenient for testing in a browser:

?api_key=sib_xxxxxxxxxxxxxxxx

Both produce identical results. The query-parameter form writes your key into browser history, server logs and any URL that gets shared, so it belongs in a scratch window rather than in code.

Rate limits

Every successful response carries the headers X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset. The counter resets at 00:00 UTC. Hitting the cap returns a 429 naming the reset time; there is no automatic upcharge and no overage fee.

List the indices

GET /v1/indices

Returns the full ticker universe with metadata. Call this first to see what exists before asking for ratios.

curl -H "x-api-key: $KEY" \
  https://siblisresearch.com/data-api/v1/indices

{
  "indices": [
    { "ticker": "DAX",  "index_name": "DAX Index",       "currency": "Local", "frequency": "daily" },
    { "ticker": "NDX",  "index_name": "NASDAQ 100 Index", "currency": "Local", "frequency": "daily" },
    { "ticker": "FTSE", "index_name": "FTSE 100 Index",   "currency": "Local", "frequency": "daily" }
  ]
}

frequency is either daily, meaning one row per trading day, or monthly, meaning one row per month-end.

One ratio for one index

GET /v1/<TICKER>/<ratio>

Not every ratio exists for every index. The Monthly Dashboard is the quickest way to check what a given ticker carries.

Two optional parameters narrow the window: from=YYYY-MM-DD and to=YYYY-MM-DD, both inclusive. They default to the first and last available dates.

curl -H "x-api-key: $KEY" \
  "https://siblisresearch.com/data-api/v1/NDX/cape?from=2020-01-01&to=2024-12-31"

{
  "ticker":     "NDX",
  "index_name": "NASDAQ 100 INDEX",
  "currency":   "USD",
  "frequency":  "daily",
  "ratio":      "cape",
  "data": [
    { "trading_day (EOD)": "2020-01-02", "value": 30.81 },
    { "trading_day (EOD)": "2020-01-03", "value": 30.63 }
  ]
}

The date field is trading_day (EOD) — the exchange trading day the ratio is calculated on, using end-of-day prices. For monthly-frequency indices it is the month-end snapshot date. Where a ratio is not provided for a ticker on a date, value is null.

Statistical aggregates

GET /v1/<TICKER>/<ratio>/stats

Returns the current reading together with the historical distribution: mean, median, standard deviation, minimum, maximum, the 10th, 25th, 75th and 90th percentile breakpoints, and the percentile rank of today's value.

{
  "ticker": "NDX",
  "ratio":  "cape",
  "current": {
    "value":             37.42,
    "trading_day (EOD)": "2025-12-31",
    "percentile_rank":   89.4
  },
  "history": {
    "from":         "1999-12-31",
    "to":           "2025-12-31",
    "observations": 6543,
    "mean":         24.83,
    "median":       24.12,
    "stddev":       6.71,
    "min":          13.32,
    "max":          44.20,
    "percentiles":  { "p10": 17.40, "p25": 20.18, "p75": 28.95, "p90": 33.71 }
  }
}

A percentile_rank of 89.4 means the current value is higher than 89.4% of all historical observations for that ticker and ratio.

Bulk CSV download

GET /v1/<TICKER>/download

Enterprise plans only. Returns a JSON envelope containing a signed URL valid for 60 minutes. Follow that URL to download the complete CSV for the ticker — every ratio, every date. The files are regenerated nightly at 23:30 UTC.

# Step 1 — get the signed URL
curl -H "x-api-key: $KEY" \
  https://siblisresearch.com/data-api/v1/NDX/download

# Step 2 — download the CSV
curl -o NDX.csv "<URL from step 1>"

CSV columns: ticker, trading_day (EOD), frequency, pe_trailing, pe_forward, cape, pb, dividend_yield, ev_ebitda.

Python

import requests

BASE = "https://siblisresearch.com/data-api/v1"
KEY  = "sib_xxxxxxxxxxxxxxxx"

def fetch(ticker, ratio, from_=None, to=None):
    params = {}
    if from_: params["from"] = from_
    if to:    params["to"]   = to
    r = requests.get(f"{BASE}/{ticker}/{ratio}",
                     headers={"x-api-key": KEY},
                     params=params, timeout=30)
    r.raise_for_status()
    return r.json()["data"]

for row in fetch("NDX", "cape", from_="2020-01-01"):
    print(row["trading_day (EOD)"], row["value"])

JavaScript

const BASE = "https://siblisresearch.com/data-api/v1";
const KEY  = "sib_xxxxxxxxxxxxxxxx";

async function fetchRatio(ticker, ratio, from, to) {
  const url = new URL(`${BASE}/${ticker}/${ratio}`);
  if (from) url.searchParams.set("from", from);
  if (to)   url.searchParams.set("to",   to);
  const res = await fetch(url, { headers: { "x-api-key": KEY } });
  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  return (await res.json()).data;
}

Excel — Power Query

Data → From Web, and paste a URL carrying the key as a query parameter. Excel parses the JSON automatically; expand the data list into rows.

https://siblisresearch.com/data-api/v1/NDX/cape?from=2020-01-01&api_key=sib_xxxxxxxxxxxxxxxx

Google Sheets

=IMPORTDATA("https://siblisresearch.com/data-api/v1/NDX/cape?api_key=sib_xxxxxxxxxxxxxxxx")

IMPORTDATA returns the raw JSON in a single cell. For a proper table, use Apps Script or a JSON-parsing add-on.

Every error returns a JSON body with a code and a human-readable message.

{
  "error":    "rate_limit_exceeded",
  "message":  "Daily call limit of 1000 reached.",
  "reset_at": "2026-06-12T00:00:00Z"
}

Three things worth knowing before you build against it

End-of-day prices, end-of-month fundamentals. Trailing P/E, forward P/E, CAPE, price to book and dividend yield are calculated daily for daily-frequency indices, using the end-of-day index price and the most recent monthly fundamentals snapshot. That snapshot carries forward across every trading day until the next one lands, so intra-month movement in these ratios is price movement.

EV/EBITDA is a monthly snapshot. It is uploaded each month rather than calculated daily, and the same value carries across every trading day until the next month's snapshot.

Trading-day calendars vary by index. December 30 may be the last trading day in one market and December 31 in another. The API returns each ticker's actual last trading day for the month rather than forcing a common calendar.

Figures are point-in-time: if a company later restates its results, the historic reading is left as it was first published.

The API guide is this page as a PDF, with the same endpoints, limits and samples — useful to keep next to the code.

Technical questions about the API go to support@siblisresearch.com. Include the exact request you ran and we will look into it.