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Playground demo key · api.reefapi.com

post/email-preflight/v1/check_images1 credit

Audit every <img> in the email: alt text presence, dimensions declared, src scheme/format, http-vs-https, and (best-effort) reachability via url-resolver. Pure-compute by default; reachability adds sub-calls.

Working example

Parameters

htmlrequired

The full HTML of the email you are about to send (paste the source). Parsed read-only in a no-network, no-script sandbox.

base_urloptional

Optional base URL: relative links/images in the HTML are resolved against it before checking.

check_reachableoptional

If true, HEAD/GET each image via url-resolver to confirm it loads (adds latency + sub-calls).

request preview

curl -X POST https://api.reefapi.com/email-preflight/v1/check_images \
  -H "x-api-key: $REEF_KEY" \
  -H "content-type: application/json" \
  -d '{"html":"<img src='https://x.test/a.png'><img src='b.png' alt='ok'>"}'

Hit Send to run this endpoint live.