Slow setJSON latency under concurrent load 1-2s PUTs to Netlify Blobs

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We use Netlify Blobs (@netlify/blobs via Edge Functions) to persist JSON results in a request/response pattern. A background worker calls PUT /api/requests/{id}/result on our Edge Function, which stores the payload via blobStores.requestResults.setJSON(id, body).
Problem: Under moderate concurrent load, setJSON takes 5–12s instead of the expected <200ms. We see:
PUT /api/requests/{id}/result 45.88 ms ← fast, no contention
PUT /api/requests/{id}/result 10175.32 ms ← 10s under 1-2 requests load
During these slow writes, everything else on the Edge Function responds normally — it’s purely the blob write that blocks. Our Edge Function’s polling loop (checking blobStores.requestResults.get(id) every 500ms with a 10s timeout) consistently times out because the write hasn’t completed yet.
Questions:

  1. Is there known latency or rate-limiting on the blob store under concurrent writes? We’re seeing maybe 3–5 concurrent PUTs.
  2. Are there any configuration options to tune retry behavior or timeouts for setJSON?
  3. Is there a recommended pattern for low-latency write-then-read flows like this using Netlify Blobs?
    Our store config:
    getDeployStore({
    name: “request-results”,
    consistency: “eventual”
    })

git repo: mztrading-data/netlify-apps/mzingest at fix-blob · mnsrulz/mztrading-data · GitHub