ureq = { version = "*", features = ["json"] }

reqwest = { version = "*", features = ["json"] }

use reqwest::{blocking::Client, header};

    let resp = ureq::post("https://api.imgflip.com/caption_image")
        .set("Content-Type", "application/x-www-form-urlencoded")
        .send_string(&url);
    let url = &resp.into_json()?["data"]["url"];

    let resp: serde_json::Value = Client::new()
        .post("https://api.imgflip.com/caption_image")
        .header(header::CONTENT_TYPE, "application/x-www-form-urlencoded")
        .body(url)
        .send()?
        .json()?;
    let url = &resp["data"]["url"];