ERCOT South Day-Ahead Price API

You need a reliable way to fetch the latest ERCOT South Day-Ahead power price and plug it straight into your finance stack. By the end of this guide you will be able to call a real Energy API endpoint, parse the ERCOT South Day-Ahead quote in USD/MWh, and productionize your integration with correct field handling, authentication, and base-currency caveats.

What the ERCOT South Day-Ahead symbol represents

The Energy API exposes ERCOT South Day-Ahead settlement pricing as a single symbol you can query in real time for the latest available observation. You will read it via one HTTPS GET call and extract the value and date from top-level JSON fields.

Illustration: ERCOT South Day-Ahead Price API

Symbol name: ERCOT South Day-Ahead
Symbol code: ERCOT_SOUTH_DA
Unit: USD/MWh
Auth: api_key query parameter (use YOUR_API_KEY as a placeholder while developing)

The endpoint you will call is GET https://energy-api.com/api/v1/latest with symbols and api_key query parameters. The latest endpoint returns a compact payload with price, currency, and date keyed by symbol.

Authentication, pricing, and key handling

Authentication is passed as a query parameter named api_key. Do not use headers for this call; the API expects the key in the query string. Use only the placeholder value YOUR_API_KEY in examples and configuration templates until you provision a key.

Starter: $19.99/mo
Trial: 7 days / 50 calls
Host: no MCP host is used or required

Register for an API key and confirm your plan limits before you ship. The links below take you directly to the correct pages with the required tracking parameters:

One-minute setup: cURL for the latest ERCOT South Day-Ahead price

This is the official call for the ERCOT South Day-Ahead symbol. Copy, paste, and replace YOUR_API_KEY with your key when you are ready:

curl -G "https://energy-api.com/api/v1/latest" --data-urlencode "symbols=ERCOT_SOUTH_DA" --data-urlencode "api_key=YOUR_API_KEY"

Interpretation guidelines:

symbols is a comma-separated list. Here we request only ERCOT_SOUTH_DA.
rates maps symbol to its latest numeric price.
dates maps symbol to the date for that price.
currencies maps symbol to its currency. For ERCOT_SOUTH_DA, the unit is USD/MWh.
base can be USD or MIXED depending on your symbol set. See the base-currency section below.

Official samples (must read before you implement)

These two blocks are official samples and should be used as-is for validation and testing. The cURL shows the request shape you must follow; the JSON shows the response structure and fields.

Official sample cURL

curl -G "https://energy-api.com/api/v1/latest" --data-urlencode "symbols=ERCOT_SOUTH_DA" --data-urlencode "api_key=YOUR_API_KEY"

Official sample JSON

{
"success": true,
"date": "2026-10-06",
"base": "EUR",
"rates": {
"OMIE_ES_DA": 206.6754
},
"dates": {
"OMIE_ES_DA": "2026-10-06"
},
"currencies": {
"OMIE_ES_DA": "EUR"
},
"base_filter_note": null
}

This example demonstrates that the response always includes:

success: boolean request status
date: the response-level date
base: the base currency context for the returned series (can be MIXED)
rates, dates, currencies: maps keyed by symbol
base_filter_note: nullable informational field

Real ERCOT sample response you can rely on

Use the following ERCOT South Day-Ahead sample to build your parser and unit tests. Copy these exact values for your fixtures.

{"success":true,"date":"2026-10-04","base":"USD","rates":{"ERCOT_SOUTH_DA":33.7679},"dates":{"ERCOT_SOUTH_DA":"2026-10-04"},"currencies":{"ERCOT_SOUTH_DA":"USD"},"base_filter_note":null}

Field usage for finance integrations:

rates.ERCOT_SOUTH_DA is the price: 33.7679 (USD per MWh)
dates.ERCOT_SOUTH_DA is the effective date: 2026-10-04
currencies.ERCOT_SOUTH_DA is USD
base is USD in this single-symbol case

Parsing the latest ERCOT South Day-Ahead quote in code

The snippet below queries the API once and extracts value, date, and currency for storage in a finance data warehouse or to feed a pricing model.

Python example

import os
import urllib.parse
import urllib.request
import json

BASE_URL = "https://energy-api.com/api/v1/latest"
params = {
"symbols": "ERCOT_SOUTH_DA",
"api_key": "YOUR_API_KEY", # replace when ready
}
url = BASE_URL + "?" + urllib.parse.urlencode(params)

with urllib.request.urlopen(url) as resp:
payload = json.loads(resp.read().decode("utf-8"))

if not payload.get("success"):
raise RuntimeError("Energy API request failed")

symbol = "ERCOT_SOUTH_DA"
price = payload["rates"][symbol]
price_date = payload["dates"][symbol]
currency = payload["currencies"][symbol]
base = payload.get("base")

print(f"ERCOT South Day-Ahead: {price} {currency}/MWh on {price_date} (base={base})")

# Example: normalize into a record you can upsert in your finance store
record = {
"symbol": symbol,
"price": float(price),
"currency": currency,
"unit": "USD/MWh",
"effective_date": price_date,
"base": base,
"as_of": payload.get("date"),
}

Key points:

Read price from rates.ERCOT_SOUTH_DA and date from dates.ERCOT_SOUTH_DA.
Store currencies.ERCOT_SOUTH_DA for downstream FX-aware analytics even if it is USD.
Use payload.date as an as-of stamp for your ingestion event.

Base currency, multi-symbol queries, and MIXED rules

For ERCOT_SOUTH_DA alone, you will typically see base: USD and currencies.ERCOT_SOUTH_DA: USD. However, when you request multiple symbols together, the API may return base: MIXED if the requested instruments are not all in the same currency.

Do not pass base=USD when you also need TTF_GAS or EUA_CO2. Those instruments can lead to a MIXED base across the response, and forcing base=USD is not supported for that case.
In MIXED responses, always read per-symbol currency from currencies.<SYMBOL> and never assume they are aligned.
Your finance pipeline should branch: if base == "MIXED", normalize per-symbol using currencies.*; otherwise you can rely on the common base.

Important: Energy owns Brent and TTF as H1 symbols; for this article, stay focused on ERCOT_SOUTH_DA when testing. If you later aggregate across power and gas, apply the MIXED rules above.

Additional JSON examples you can paste into tests

These complete response examples use the exact structure and values shown above so you can copy them into unit tests and contract tests without changing your parsing logic.

ERCOT South Day-Ahead (fixture 1)

{"success":true,"date":"2026-10-04","base":"USD","rates":{"ERCOT_SOUTH_DA":33.7679},"dates":{"ERCOT_SOUTH_DA":"2026-10-04"},"currencies":{"ERCOT_SOUTH_DA":"USD"},"base_filter_note":null}

Official structure example (fixture 2)

{
"success": true,
"date": "2026-10-06",
"base": "EUR",
"rates": {
"OMIE_ES_DA": 206.6754
},
"dates": {
"OMIE_ES_DA": "2026-10-06"
},
"currencies": {
"OMIE_ES_DA": "EUR"
},
"base_filter_note": null
}

ERCOT South Day-Ahead (fixture 3, identical for deterministic tests)

{"success":true,"date":"2026-10-04","base":"USD","rates":{"ERCOT_SOUTH_DA":33.7679},"dates":{"ERCOT_SOUTH_DA":"2026-10-04"},"currencies":{"ERCOT_SOUTH_DA":"USD"},"base_filter_note":null}

Official structure example (fixture 4, identical for schema validation)

{
"success": true,
"date": "2026-10-06",
"base": "EUR",
"rates": {
"OMIE_ES_DA": 206.6754
},
"dates": {
"OMIE_ES_DA": "2026-10-06"
},
"currencies": {
"OMIE_ES_DA": "EUR"
},
"base_filter_note": null
}

JavaScript example: fetch and normalize into a finance record

This Node.js example uses the global fetch (Node 18+) to retrieve and parse the ERCOT South Day-Ahead quote. It extracts price, currency, and date into a plain object suitable for a pricing service or a finance data lake.

import { URLSearchParams } from "node:url";

const BASE_URL = "https://energy-api.com/api/v1/latest";
const params = new URLSearchParams({
symbols: "ERCOT_SOUTH_DA",
api_key: "YOUR_API_KEY", // replace in production
});

const res = await fetch(`${BASE_URL}?${params.toString()}`);
if (!res.ok) {
throw new Error(`HTTP ${res.status}`);
}
const payload = await res.json();
if (!payload.success) {
throw new Error("Energy API request failed");
}

const symbol = "ERCOT_SOUTH_DA";
const record = {
symbol,
price: payload.rates[symbol],
currency: payload.currencies[symbol],
unit: "USD/MWh",
effective_date: payload.dates[symbol],
base: payload.base, // e.g., "USD" or "MIXED"
as_of: payload.date, // response-level date
};

console.log(record);

Implementation notes:

Keep symbol as a constant to avoid typos in object traversal.
Do not coerce currency or base; propagate them as returned.
If you later add more symbols, pivot on payload.base to decide normalization behavior.

Practical integration details that save time

Units: ERCOT_SOUTH_DA quotes are USD per MWh. Store the unit string alongside the value for auditability.
Timestamps and dates: Use dates.ERCOT_SOUTH_DA as the effective observation date for finance postings and backfills. Use the top-level date as an ingestion-as-of stamp.
Caching: For server-side apps, cache the last successful payload to tolerate transient network errors. Since this is a latest endpoint, avoid overly aggressive caching for real-time dashboards.
Non-trading days and data gaps: If the market does not produce a new settlement on a given date, expect the API to reflect the last available observation date in dates.ERCOT_SOUTH_DA. Do not assume daily continuity; handle unchanged dates correctly.
Pagination: Not applicable for this endpoint; the latest API returns a compact single-page JSON for the symbols you request.
Error handling: Check success first. If success is false, do not read rates or dates; retry or log.

Validating your parser with schema-aware checks

Before wiring your downstream finance logic, add guards that confirm the expected fields and types exist. These guardrails prevent silent mis-keys when adding symbols or handling MIXED responses.

Required maps: rates, dates, currencies. Each must contain the ERCOT_SOUTH_DA key.
Types: rates.ERCOT_SOUTH_DA is numeric; dates.ERCOT_SOUTH_DA is YYYY-MM-DD string; currencies.ERCOT_SOUTH_DA is a 3-letter code.
Base: allow USD or MIXED. If MIXED, do not perform any cross-symbol arithmetic without per-symbol currency handling.

Combining ERCOT South with additional instruments

You may eventually query ERCOT_SOUTH_DA alongside other power or emissions instruments. The same endpoint supports comma-separated symbols. Keep these rules in place when you expand:

Do not pass base=USD when you also need TTF_GAS or EUA_CO2. The response may rightfully be MIXED; honor per-symbol currencies.
For finance use cases that aggregate P&L across instruments, convert each price using currencies.* to your reporting currency after retrieval, not via a base parameter on the call.

Energy owns Brent and TTF as H1 symbols; those are available if you expand coverage. For this guide, keep your tests on ERCOT_SOUTH_DA to validate the ingestion path first.

Operational playbook: retries, observability, and change control

Once you have a working proof-of-concept, productionize it with these measures:

Retries: Apply a small bounded retry policy on network failures. Do not retry indefinitely if success is false; surface the error and retain the last good value in a cache for continuity.
Idempotent writes: Use symbol + dates.ERCOT_SOUTH_DA as an idempotency key in your finance database so repeated ingests do not duplicate records.
Monitoring: Track a counter for successful vs failed fetches and alert if failures exceed a short rolling window.
Backfills: The latest endpoint is for current observations. For historical backfills, consult the API documentation to select the appropriate route before bulk loading.

Field-by-field walkthrough using the real ERCOT response

Revisit the real ERCOT sample and verify your extraction logic against each field you will persist:

{"success":true,"date":"2026-10-04","base":"USD","rates":{"ERCOT_SOUTH_DA":33.7679},"dates":{"ERCOT_SOUTH_DA":"2026-10-04"},"currencies":{"ERCOT_SOUTH_DA":"USD"},"base_filter_note":null}

Persist price as a decimal number: 33.7679
Persist effective_date: 2026-10-04
Persist currency: USD and unit: USD/MWh
Store base unchanged (USD) for audit and future mixed queries

Copy-and-paste: the authoritative cURL for ERCOT South

Keep a ready-to-run CLI tester for diagnostics and data inspection:

curl -G "https://energy-api.com/api/v1/latest" --data-urlencode "symbols=ERCOT_SOUTH_DA" --data-urlencode "api_key=YOUR_API_KEY"

Use this exact form when debugging production issues so your test mirrors application behavior. Because authentication is via query string, verify that logs and dashboards redact YOUR_API_KEY when capturing URLs.

FAQ

Q: Which fields should I read to price ERCOT South Day-Ahead?
A: Read rates.ERCOT_SOUTH_DA for the numeric price, dates.ERCOT_SOUTH_DA for the effective date, and currencies.ERCOT_SOUTH_DA for the currency (USD). Use base to determine whether the response is USD or MIXED.

Q: Can I force all instruments to USD with a base parameter?
A: Do not pass base=USD when you also need TTF_GAS or EUA_CO2. If you query mixed-currency instruments together, the response may return base: MIXED. Normalize per symbol using currencies.* in your code.

Q: How often should I poll the latest endpoint?
A: The latest endpoint returns the most recent observation. Poll at a cadence that matches your finance workflow and plan limits. Use lightweight caching to avoid redundant calls when the date has not advanced.

Q: What happens on weekends or holidays?
A: Treat dates.ERCOT_SOUTH_DA as the source of truth for the effective observation date. Do not assume a new value is available every calendar day; handle unchanged dates without duplicating records.

Q: Where do I find full parameter and field documentation?
A: See the official Documentation for endpoint details and any additional options beyond symbols and api_key.

Ready to wire ERCOT South Day-Ahead into your finance systems? Create your key and ship with the production-ready snippets above. Start here: Register and review the Documentation to confirm symbols and response fields.