New York Independent System Operator (NYISO)

NYISO Finance Invoicing API

The Invoicing component of NYISO's Finance APIs, retrieving daily reconciliation data for both settlements dollars and energy volumes. The published guide documents GET /v1/dailyReconciliation/dollar and GET /v1/dailyReconciliation/mwh, parameterised by start date and an optional version, returning JSON with two decimals of dollar precision and four decimals of MWh precision. Restricted to NYISO market participants - MIS user account and password via HTTP Basic plus the associated NAESB certificate on every request. Both the root and /v1/dailyReconciliation/dollar returned 401 Authorization Required to anonymous probes on 2026-07-27.

GitHub

Documentation

📖
Documentation
https://www.nyiso.com/documents/20142/45334160/NYISO%20Finance%20APIs%20User's%20Guide%20v1.2%20-%20DRAFT.pdf/4f0de58a-783d-a317-64fe-caed77ba61fa
📖
Documentation
https://www.nyiso.com/billings-and-settlements
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APIReference
https://www.nyiso.com/documents/20142/45334160/NYISO%20Finance%20APIs%20User's%20Guide%20v1.2%20-%20DRAFT.pdf/4f0de58a-783d-a317-64fe-caed77ba61fa

Other Resources

🔗
Sandbox
https://raw.githubusercontent.com/api-evangelist/nyiso/refs/heads/main/sandbox/nyiso-sandbox.yml

API entry from apis.yml

apis.yml Raw ↑ 
aid: nyiso:nyiso-finance-invoicing-api
name: NYISO Finance Invoicing API
description: The Invoicing component of NYISO's Finance APIs, retrieving daily reconciliation data for
  both settlements dollars and energy volumes. The published guide documents GET /v1/dailyReconciliation/dollar
  and GET /v1/dailyReconciliation/mwh, parameterised by start date and an optional version, returning
  JSON with two decimals of dollar precision and four decimals of MWh precision. Restricted to NYISO market
  participants - MIS user account and password via HTTP Basic plus the associated NAESB certificate on
  every request. Both the root and /v1/dailyReconciliation/dollar returned 401 Authorization Required
  to anonymous probes on 2026-07-27.
humanURL: https://www.nyiso.com/documents/20142/45334160/NYISO%20Finance%20APIs%20User's%20Guide%20v1.2%20-%20DRAFT.pdf/4f0de58a-783d-a317-64fe-caed77ba61fa
baseURL: https://api.nyiso.com/finance/invoicing
tags:
- Invoicing
- Settlements
- Electricity
- Market Participants
properties:
- type: Documentation
  url: https://www.nyiso.com/documents/20142/45334160/NYISO%20Finance%20APIs%20User's%20Guide%20v1.2%20-%20DRAFT.pdf/4f0de58a-783d-a317-64fe-caed77ba61fa
- type: Documentation
  url: https://www.nyiso.com/billings-and-settlements
- type: APIReference
  name: Finance APIs User's Guide v1.2 (Invoicing - daily reconciliation endpoints)
  url: https://www.nyiso.com/documents/20142/45334160/NYISO%20Finance%20APIs%20User's%20Guide%20v1.2%20-%20DRAFT.pdf/4f0de58a-783d-a317-64fe-caed77ba61fa
- type: Sandbox
  name: API Market Trial environment (apitest.nyiso.com)
  url: sandbox/nyiso-sandbox.yml