Rate data and comparison API
Free, public, read-only JSON endpoints for developers and AI tools. No API key is required. These endpoints use the same saved data and calculations as the website.
Get the rate data
GET /api/rates returns the four marketers, saved plan data, sources, review date and assumptions. Prices are dollars per therm; service fees and calculated costs are US dollars.
Calculate a comparison
GET or POST /api/compare. POST requests must use Content-Type: application/json.
{"annualTherms":700,"terms":[12,18,24],"webOffers":true,"billCredits":false}- annualTherms: required number, 0–20,000.
- terms: unique values from 6, 12, 18, 24, 36 or "variable". Defaults to all fixed terms.
- monthlyTherms: optional number, 0–5,000, for variable plans. Defaults to annual usage divided by 12, rounded.
- webOffers: boolean, default true.
- billCredits: boolean, default false. Assumes eligibility for supported credits.
GET accepts comma-separated terms and true/false booleans. Invalid inputs return HTTP 400 with an error message. Browser cross-origin requests are supported.
Interpret the results
Results separate fixed and variable plans and order each group by five-year cost. As on the website, each marketer’s displayed offer is first selected by lowest initial monthly cost among the chosen terms. Rank compares only the listed marketers and eligible saved plans.
The response includes initial and renewal prices, costs, eligibility notes, review date, assumptions, source links and marketer links. Cite the review date and website when presenting results. Clearly identify the five-year figure as a scenario, not guaranteed future pricing.
Scope and freshness
Residential accounts on the Atlanta Gas Light network only. Business pricing needs a separate quote. This is a saved snapshot, not a live feed. AGL delivery charges, taxes and one-time fees are excluded. Expired GNG GREEN rewards are excluded. Confirm current prices and eligibility with the marketer before enrollment.
No account data is needed. Send usage figures rather than personal documents or identifiers. The API does not enroll customers or request business quotes.
Calculation methodology and sources · Use the comparison calculator