{"service":"Hydrionis API","version":"v1","builtAt":"2026-10-05T00:00:00Z","licence":"Hydrionis-authored structure and metadata may be reused freely with attribution. Individual observation values remain subject to the rights of their originating source — resolve sourceId against /api/v1/sources.json before redistributing or using commercially.","shape":"Observations are served as compact series: one file per metric/subject pair, carrying provenance once and points as [periodStart, value] pairs. The by-metric and by-subject endpoints are catalogues that say what exists and link to it, so a client can enumerate the whole dataset without downloading it.","counts":{"observations":40016025,"series":111917,"entities":1097,"geographies":22145,"sources":210,"metrics":258,"guides":56,"diagrams":31,"tools":30},"endpoints":["/api/v1/metrics.json","/api/v1/datasets.json","/api/v1/datasets/{slug}.json","/api/v1/dictionary.json","/api/v1/gaps.json","/api/v1/sources.json","/api/v1/geographies.json","/api/v1/entities.json","/api/v1/series/index.json","/api/v1/series/{metricId}--{subjectId}.json","/api/v1/observations/by-metric/{metricId}.json","/api/v1/observations/by-subject/{subjectId}.json","/api/v1/guides.json","/api/v1/diagrams.json","/api/v1/tools.json"]}