{"name":"Agent Playground APIs","updated":"2026-09-02","purpose":"APIs an agent registered with the APIs.io network can safely call while learning — no key or an instant self-serve key, no cost, low blast radius, real data.","how_to_use":"Every entry's `example_request` is a URL that returned HTTP 200 to an unauthenticated GET from TWO different HTTP clients, on the date in `verified`, and is re-proved nightly. Call it directly — no key, no signup, no cost. `access: instant-key` means a key exists but is self-serve and free. Start with `grouping: starter`. Entries that failed their last check are withheld; pass include_unverified=true to see them with their `drift` note.","safety":"Curated to be safe to experiment with: no money movement, no health data, no messaging side-effects, no ad spend, no identity checks. Read-dominant surfaces only.","docs":"https://apis.io/playground","total":12,"apis":[{"slug":"scryfall","name":"Scryfall","good_for":"Magic: The Gathering card data. Large, clean, generous — a good first tool call.","access":"no-key","grouping":"starter","tags":["Games And Comics","Magic The Gathering","Card Data","Open Data","Free","Community Funded"],"kin_score":57.6,"kin_band":"strong","mcp_server":false,"example_request":"https://api.scryfall.com/bulk-data","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/scryfall"},{"slug":"usgs-water","name":"USGS Water Services","good_for":"US streamflow, groundwater and water-quality observations via OGC API.","access":"no-key","grouping":"starter","tags":["Water","Streamflow","Groundwater","Water Quality","Hydrology","Environmental"],"kin_score":48.6,"kin_band":"developing","mcp_server":false,"example_request":"https://api.waterdata.usgs.gov/ogcapi/v0/collections/agency-codes","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/usgs-water"},{"slug":"arxiv","name":"arXiv","good_for":"Preprint metadata across physics, maths and computer science (OAI-PMH).","access":"no-key","grouping":"starter","tags":["Science And Math","Scholarly Publishing","Preprints","Open Access","Research","Open-Source"],"kin_score":47.8,"kin_band":"developing","mcp_server":false,"example_request":"https://oaipmh.arxiv.org/oai?verb=Identify","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/arxiv"},{"slug":"bls","name":"Bureau of Labor Statistics","good_for":"US Bureau of Labor Statistics — employment, wages, prices, productivity.","access":"no-key","grouping":"starter","tags":["Bureau of Labor Statistics","BLS","Employment","Unemployment","CPI","Consumer Price Index"],"kin_score":47.5,"kin_band":"developing","mcp_server":false,"example_request":"https://api.bls.gov/publicAPI/v2/surveys","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/bls"},{"slug":"datamuse","name":"Datamuse","good_for":"Word and phrase lookup: rhymes, synonyms, spelling. Tiny responses, ideal for chained calls.","access":"no-key","grouping":"starter","tags":["Word Finding","Lexical Search","Natural-Language","Vocabulary","Synonyms","Antonyms"],"kin_score":47.4,"kin_band":"developing","mcp_server":false,"example_request":"https://api.datamuse.com/sug","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/datamuse"},{"slug":"openhands","name":"OpenHands","good_for":"Liveness/status surface for the OpenHands agent platform.","access":"instant-key","grouping":"starter","tags":["Artificial Intelligence","Agents","Autonomous","Open-Source","Developer Tools","Software Engineering"],"kin_score":45.2,"kin_band":"developing","mcp_server":false,"example_request":"https://app.all-hands.dev/alive","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/openhands"},{"slug":"yr-no","name":"Yr","good_for":"Norwegian Meteorological Institute forecasts. Requires a real, identifying User-Agent.","access":"no-key","grouping":"starter","tags":["Weather","Forecast","Meteorology","Climate","Norway","Nordic"],"kin_score":43.3,"kin_band":"developing","mcp_server":false,"example_request":"https://api.met.no/weatherapi/locationforecast/2.0/current","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/yr-no"},{"slug":"elexon","name":"Elexon","good_for":"UK electricity balancing market data — settlement, generation, demand.","access":"no-key","grouping":"starter","tags":["Electricity","Energy","UK Energy Market","Balancing Mechanism","Settlement","Meter Readings"],"kin_score":42.2,"kin_band":"developing","mcp_server":false,"example_request":"https://data.elexon.co.uk/bmrs/api/v1/balancing/acceptances/all/latest","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/elexon"},{"slug":"bls-gov","name":"Bureau of Labor Statistics","good_for":"BLS popular time series, keyed by series id.","access":"no-key","grouping":"starter","tags":["Federal-Government","Labor Statistics","Economic Data","Consumer Price Index","Producer Price Index","Employment"],"kin_score":41.3,"kin_band":"developing","mcp_server":false,"example_request":"https://api.bls.gov/publicAPI/v2/timeseries/popular","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/bls-gov"},{"slug":"openapi-generator","name":"OpenAPI Generator","good_for":"Generate a client SDK from an OpenAPI document.","access":"no-key","grouping":"starter","tags":["Code Generation","Documentation","Open-Source","OpenAPI","SDK","API Tooling"],"kin_score":40.7,"kin_band":"developing","mcp_server":true,"example_request":"https://api.openapi-generator.tech/api/gen/clients","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/openapi-generator"},{"slug":"frankfurter","name":"Frankfurter","good_for":"Foreign exchange reference rates, current and historical.","access":"no-key","grouping":"starter","tags":["Currency Exchange","Foreign Exchange","FX","Open-Source","MIT","Self-Hosted"],"kin_score":40.4,"kin_band":"developing","mcp_server":false,"example_request":"https://api.frankfurter.dev/v1/currencies","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/frankfurter"},{"slug":"carbon-intensity","name":"Carbon Intensity API","good_for":"Live carbon intensity of the UK electricity grid, with forecasts.","access":"no-key","grouping":"starter","tags":["Carbon Intensity","Environment","Energy","Electricity","Climate","Great Britain"],"kin_score":40,"kin_band":"developing","mcp_server":false,"example_request":"https://api.carbonintensity.org.uk/intensity/factors","verified":"2026-09-02","drift":null,"provider_page":"https://apis.io/provider/carbon-intensity"}],"withheld":1,"withheld_note":"1 entry failed the last nightly check and is withheld. Pass include_unverified=true to see them with the reason."}