Pass source steam for a monthly concurrent-player series, or source youtube for a weekly search-interest series. Steam can fold several game strings onto one chart. YouTube keeps each string separate.
Live data as of 2026-09-28
Source steam on get_growth and get_time_series returns a monthly concurrent-player series for a game display name. Source youtube returns a weekly 0-100 YouTube search-interest series for the same string and omits volume. On 2026-09-28, Counter-Strike 2 closed 73.8 / 1,331,274 players on Steam (recent_date 2026-08-01, 170 monthly points from 2012-07-01) and 8.0 on YouTube (recent_date 2026-09-26, 261 weekly points from 2021-10-02, no volume). Steam folded CS2, cs2, and App ID 730 onto that player series. YouTube treated each string as a different search phrase (CS2 closed 62.0). The live boards use type Steam Most Played and type YouTube Trending, not those source strings.
Steam resolved four spellings to one concurrent-player chart. Keywords Counter-Strike 2, CS2, cs2, and 730 each returned 170 monthly points from 2012-07-01 through 2026-08-01, index 73.8, volume 1,331,274. Peak index sat at 100.0 on 2023-05-01 (volume 1,802,853). Peak volume sat later, 1,818,368 on 2025-03-01 at index 93.0. The series field is datatype steam, not source.
YouTube kept the strings apart. Counter-Strike 2 closed 8.0 on 2026-09-26 (261 weekly points from 2021-10-02, open 0, peak 100 on 2023-03-25). CS2 and cs2 closed 62.0 (peak 100 on 2023-10-07). 730 closed 42.0 (open 41 on 2021-10-02, peak 100 on 2023-02-11). None of those YouTube rows carried a volume key. The series field is source youtube, with no datatype.
A hash prefix is not a free alias. Steam #Counter-Strike 2 still closed 73.8 / 1,331,274 with 170 points. Steam #CS2 did not. That call returned 106 monthly points from 2017-11-01 through 2026-08-01, close 0.0 / 22 players, 12M minus 100 percent. YouTube #CS2 closed 53.0 on 2026-09-26. Its 12M row printed growth 999999.0 because the baseline on 2025-09-27 was 0.0. Read that sentinel as a zero baseline, not as a million-percent audience.
Source names case-fold. Steam, STEAM, YouTube, and YOUTUBE on get_growth for Counter-Strike 2 returned the same 12M rows as the lowercase labels. Feed labels do not belong here. Source Steam Most Played and source YouTube Trending returned HTTP 400 invalid_source, echoed in lowercase, and listed the 16 keyword sources plus all.
Omitting percent_growth defaults to 12M on both sources. Steam Counter-Strike 2 returned 73.8 from 83.1, minus 11.19 percent, volume 1,331,274 from 1,502,245, volume_growth minus 11.38 percent, 170 points. YouTube returned 8.0 from 10.0, minus 20.0 percent, 261 points, no volume fields.
Short windows split. Steam 7D, 1W, 14D, and 2W each returned collapsed_range with the message that recent and baseline resolved to the same data point. Steam 30D matched 1M: 73.8 from 76.3, minus 3.28 percent, volume_growth minus 6.31 percent. Steam YTD was 73.8 from 95.8, minus 22.96 percent, volume 1,331,274 from 1,654,355. YouTube 7D matched 1W (8.0 from 6.0, plus 33.33 percent). YouTube 14D matched 2W (8.0 from 6.0, plus 33.33 percent). YouTube 30D matched 1M (8.0 from 7.0, plus 14.29 percent). YouTube YTD was 8.0 from 6.0, plus 33.33 percent. The two calendars do not share a close. Steam's last row is 2026-08-01. YouTube's last row is 2026-09-26.
Other titles repeat the grain. Dota 2, rank 2 on the Steam Most Played board that morning, closed 86.0 / 981,123 on Steam (170 points, 30D plus 14.51 percent, 12M plus 17.65 percent) and 24.0 on YouTube (261 points, 7D plus 20.0 percent, 12M 0.0 percent). Elden Ring closed 1.8 / 52,385 on Steam (54 points) with 12M index minus 14.29 percent and volume_growth plus 3.43 percent. YouTube Elden Ring closed 6.0 with 12M plus 20.0 percent. Index and player count can move in opposite directions on steam. YouTube has only the index.
Grand Theft Auto V shows a short Steam history. Steam returned 18 monthly points, close 46.2 / 100,696, 12M plus 396.77 percent from 9.3. YouTube returned the usual 261 weekly points, close 24.0, 12M plus 14.29 percent. A 12M window can still succeed on steam when the series is longer than a year. It does not make the two indexes comparable.
{"mode": "get_growth", "source": "steam, youtube", "keyword": "Counter-Strike 2", "percent_growth": ["7D", "12M"]}
That comma call on 2026-09-28 returned sources_successful 2. Steam still errored on 7D (collapsed_range) and succeeded on 12M (index minus 11.19 percent, volume_growth minus 11.38 percent). YouTube succeeded on both windows (7D plus 33.33 percent, 12M minus 20.0 percent). trend_analysis printed uptrend_count 1 and downtrend_count 1. volume_weighted_growth was minus 11.38 with weight_coverage 1/2 sources and total_volume 1,331,274.0. The only weighted row was steam, at 100 percent of that volume, using steam's 12M volume_growth. YouTube's 7D jump never entered the blend because YouTube has no volume.
Elden Ring on steam, youtube with 12M repeated the shape: sources_successful 2, volume_weighted_growth plus 3.43, steam volume 52,385.0 at 100 percent, coverage 1/2 sources. That 3.43 is steam volume_growth, not steam index growth (minus 14.29 percent) and not YouTube 12M (plus 20.0 percent). Do not chart the blended number as a two-platform 12M.
get_time_series rejects the comma. Source steam, youtube returned HTTP 400 invalid_source and listed 16 keyword sources with no all. One source per series call. Two sources belong on get_growth.
Type Steam Most Played and type YouTube Trending on get_top_trends take no keyword. Omitting limit on both returned limit 25, count 25, offset 0, and the same as_of_ts 2026-09-28T06:01:36.476311+00:00. Steam rank 1 was Counter-Strike 2. Rank 2 was Dota 2. Rank 3 was PUBG: BATTLEGROUNDS. YouTube rank 1 was a KATSEYE Saturday Night Live clip. Rank is live order, not a sort of the August Steam close or the 2026-09-26 YouTube index.
Mixing the strings fails. Type steam, type Steam, type youtube, and type YouTube each returned HTTP 400 invalid_request and listed 24 valid feed names. Type youtube trending (lowercase) 200-aliased to YouTube Trending with the same stamp and rank 1 title. Source steam is not a feed type. Type Steam Most Played is not a growth source. The monthly series against that Steam board lives on source steam vs type Steam Most Played. The two live boards against each other live on Steam Most Played vs YouTube Trending.
country GB with limit 3 on YouTube Trending returned HTTP 200, echoed country GB, and stamped as_of_ts 2026-09-28T06:24:17.487920+00:00. Rank 1 was the same KATSEYE title. That stamp is later than the omitted-country 06:01:36 snapshot. The same country GB on Steam Most Played returned HTTP 400 invalid_request: country is only supported for Google Trends, Google Trends by Category, TikTok Trending Hashtags, TikTok Trending Hashtags by Category, X (Twitter) Trending, and YouTube Trending. Omit country on Steam Most Played.
REST omitting type is a different 400. POST https://api.trendsmcp.ai/api with mode get_top_trends and limit 5, no type, returned HTTP 200 with envelope statusCode 400, error invalid_request, message The 'type' parameter is required, then the same 24-name list. llms.txt still names that miss missing_parameter. Read statusCode inside the JSON, not only the HTTP line.
YouTube accepts any phrase. Steam needs a game the SteamCharts path can resolve. Keyword Fortnite on steam returned HTTP 404 no_data. The same string on youtube closed 15.0 on 2026-09-26 (261 points, 12M minus 6.25 percent). Keyword chatgpt on steam returned the same 404. YouTube chatgpt closed 53.0, 12M plus 130.43 percent from 23.0. Keyword TBH on steam returned 404. YouTube TBH closed 41.0. A YouTube hit does not prove a Steam player series exists.
Minecraft on steam returned HTTP 502 source_unavailable (SteamCharts request failed: 500) on this pull. YouTube Minecraft closed 7.0 with 261 points. Treat that Steam miss as a source-health flag, not as proof the title is absent. Retry later. Wallpaper Engine closed 88.1 / 117,596 on Steam (120 points, 12M minus 11.72 percent) and 29.0 on YouTube (261 points, 12M minus 9.38 percent). PUBG: BATTLEGROUNDS closed 19.4 / 771,621 on Steam (114 points, 12M plus 9.6 percent) and 36.0 on YouTube (261 points, 12M plus 80.0 percent). Baldur's Gate 3 closed 10.9 / 83,011 on Steam (71 points) and 5.0 on YouTube with a flat 7D/30D/12M index.
get_growth bills one request per source plus keyword, including every window inside percent_growth. A two-source comma string is two units. get_time_series bills one request per source plus keyword. get_top_trends MCP pricing is 1 credit per 10 requested rows, max 10 credits per call. REST counts 1 request per call. The Free plan covers 100 requests per month. Starter is $19 for 1,000 requests, Pro is $49 for 5,000, and Business is $199 for 25,000. Keyword follow-up for the search index stays on YouTube search data.
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