The X API is a content API with tiered access: post lookup, search, and posting, priced for apps that read and write X. For trend work the shape is wrong from the start. The legacy trends endpoints are not on current self-serve tiers, and mention counts need search access plus your own storage. Trends API serves the trend layer: X (Twitter) Trending as a live board from one POST, plus 16 keyword sources across other platforms on the same key. Request shape is on the API reference.
What happened to X API access
X's API tiers changed in 2023 and read access moved behind paid plans with post caps. The exact tiers and prices change, so check X's current developer pricing before designing around it. Two gaps matter for trend work: the old trends endpoints are not part of self-serve access, and any mention-count series needs search access, polling, and a normalization layer you operate yourself.
The trending board as one call
POST https://api.trendsapi.ai/api
Authorization: Bearer <api_key>
Content-Type: application/json
{"mode":"get_top_trends","type":"X (Twitter) Trending","limit":10}
A live pull on 2026-09-20 returned an NFL-heavy board: Chargers, Jayden Daniels, Justin Herbert, Raiders, and Dan Quinn in the top five, with Browns, Caleb, Jets, Ravens, and Tom Brady completing the top ten. body is a JSON string and must be parsed a second time. sort rank_change surfaces climbers against a prior snapshot. Feed options are on the live feeds reference.
What Trends API does not do on X
There is no per-keyword X mention volume here. The X coverage is the trending-topics board. For per-keyword measurement the sources are Google, TikTok, Reddit, YouTube, Amazon, and the rest, all on the same 0-100 scale. "Did the X buzz show up in search?" is one board call plus one get_growth call. The endpoint-by-endpoint version is X trending without the X API.
When the X API is the right tool
Keep the X API when the product posts, reads specific threads, or hydrates posts by ID. Switch when the question is what is trending now, or how X attention compares with search and social. X's current tiers are on its developer site; Trends API caps sit on pricing. The cross-platform walkthrough is creator trends.