R httr2: POST /v1/images on Sume without throwing on a 502

R users generating plot backgrounds or report art can call the API with httr2 in a few lines.

The request is the same in every language: POST https://api.sume.com/v1/images with a bearer key from SUME_API_KEY, a JSON body with model, prompt and aspect_ratio, and a client timeout above the route's 30-second wait. The route defaults to mode: "sync", so the status code decides what you do next (docs read 2026-10-07):

Status codes to branch on

R code

Save as gen.R and run SUME_API_KEY=... Rscript gen.R, with the httr2 package installed (the native pipe needs R 4.1 or newer).

library(httr2)

key <- Sys.getenv("SUME_API_KEY")
if (!nzchar(key)) stop("SUME_API_KEY missing")

resp <- request("https://api.sume.com/v1/images") |>
  req_auth_bearer_token(key) |>
  req_body_json(list(
    model = "bytedance-seed/seedream-5-lite",
    prompt = "matte ceramic mug on a white sweep, soft shadow",
    aspect_ratio = "16:9"
  )) |>
  req_timeout(40) |>
  req_error(is_error = function(resp) FALSE) |>
  req_perform()

status <- resp_status(resp)
if (status == 200) {
  cat("done:", resp_body_json(resp)$data[[1]]$url, "\n")
} else if (status == 202) {
  cat("queued, follow status_url:", resp_body_string(resp), "\n")
} else {
  cat("error", status, resp_body_string(resp), "\n")
}

Notes

By default httr2 raises an error on 4xx and 5xx. req_error(is_error = function(resp) FALSE) turns that off so you can read the error body, which includes code, retryable and next_action.

A 202 is not an error. It is a job envelope; read the file from its result_url after the job completes.

One bytedance-seed/seedream-5-lite image is $0.04375 billed (list $0.035 x 1.25). Prices here are Sume's list-times-1.25 figures. The catalog states the billable formula as "list × 1.25 → ceil usd cents", so treat the dollar amounts as the pre-rounding value and read the exact charge from billable_amount_usd_micros in the submit envelope. Failed or cancelled generations are not billed.

Sources: Sume Image API docs and Jobs and results (read 2026-10-07).