Seems not to be on the endpoint. I get this in a browser
{"response":{"total":24,"dateFormat":"YYYY","frequency":"annual","data":[{"period":2024,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20693.69,"sales-units":"million kilowatt hours"},{"period":2023,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":19999.33299,"sales-units":"million kilowatt hours"},{"period":2022,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20593.94201,"sales-units":"million kilowatt hours"},{"period":2021,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20625.00501,"sales-units":"million kilowatt hours"},{"period":2020,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20482.50199,"sales-units":"million kilowatt hours"},{"period":2019,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":19404.743,"sales-units":"million kilowatt hours"},{"period":2018,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":19286.95201,"sales-units":"million kilowatt hours"},{"period":2017,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18614.99999,"sales-units":"million kilowatt hours"},{"period":2016,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18833.722,"sales-units":"million kilowatt hours"},{"period":2015,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18384.93601,"sales-units":"million kilowatt hours"},{"period":2014,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18092.93201,"sales-units":"million kilowatt hours"},{"period":2013,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18528.908,"sales-units":"million kilowatt hours"},{"period":2012,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18220.36501,"sales-units":"million kilowatt hours"},{"period":2011,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18276.79899,"sales-units":"million kilowatt hours"},{"period":2010,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":18102.386,"sales-units":"million kilowatt hours"},{"period":2009,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":17412.63,"sales-units":"million kilowatt hours"},{"period":2008,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":17720.491,"sales-units":"million kilowatt hours"},{"period":2007,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":17634.182,"sales-units":"million kilowatt hours"},{"period":2006,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":16951.534,"sales-units":"million kilowatt hours"},{"period":2005,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":16436.381,"sales-units":"million kilowatt hours"},{"period":2004,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":15532.168,"sales-units":"million kilowatt hours"},{"period":2003,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":15724.839,"sales-units":"million kilowatt hours"},{"period":2002,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":15424.846,"sales-units":"million kilowatt hours"},{"period":2001,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":14470.251,"sales-units":"million kilowatt hours"}],"description":"Electricity sales to ultimate customer by state and sector (number of customers, average price, revenue, and megawatthours of sales). \n Sources: Forms EIA-826, EIA-861, EIA-861M","id":"retail-sales"},"request":{"command":"\/v2\/seriesid\/ELEC.SALES.CO-RES.A","params":{"frequency":"annual","data":["sales"],"facets":{"sectorid":["RES"],"stateid":["CO"]},"start":null,"end":null,"sort":[{"column":"period","direction":"desc"}],"offset":0,"length":5000,"api_key":"jj5NBhhIogCYhpgHCfeF5osMLAmqf7GbxSnGgtV7"},"route":"electricity\/retail-sales"},"apiVersion":"2.1.10","ExcelAddInVersion":"2.1.0"}
and from HTTP, I get
HTTP.Messages.Response:
"""
HTTP/1.1 200 OK
Date: Tue, 02 Dec 2025 01:21:11 GMT
Content-Type: application/json
Content-Length: 795
Connection: keep-alive
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept, Authorization, X-Params
Access-Control-Allow-Methods: GET,POST,PATCH,PUT,DELETE,OPTIONS
Access-Control-Allow-Origin: *
Age: 3
Cache-Control: max-age=0, no-cache, no-store
Content-Encoding: gzip
Expires: Tue, 02 Dec 2025 01:21:11 GMT
Pragma: no-cache
Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
Vary: Accept-Encoding, Accept-Encoding
Via: https/1.1 api-umbrella (ApacheTrafficServer [cMsSf ])
X-Api-Umbrella-Request-Id: cqrij2jlporgvtlkkicg
X-Cache: MISS
X-Content-Type-Options: nosniff
X-Vcap-Request-Id: 6efaf6bf-6e19-4e51-5f9f-c7521bab71d6
X-Frame-Options: SAMEORIGIN
{"response":{"total":24,"dateFormat":"YYYY","frequency":"annual","data":[{"period":2024,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20693.69,"sales-units":"million kilowatt hours"},{"period":2023,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":19999.33299,"sales-units":"million kilowatt hours"},{"period":2022,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20593.94201,"sales-units":"million kilowatt hours"},{"period":2021,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20625.00501,"sales-units":"million kilowatt hours"},{"period":2020,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales":20482.50199,"sales-units":"million kilowatt hours"},{"period":2019,"stateid":"CO","stateDescription":"Colorado","sectorid":"RES","sectorName":"residential","sales
⋮
4592-byte body