429 — Too Many Requests — rate limited

The request was rejected for exceeding a rate limit. Limits apply per key, and separately per IP for keyless access.

Start free HTTP / REST → canonical

Diagnosis

When you hit this

A polling loop faster than the plan allows.
Keyless normalization beyond the low daily per-IP cap.
A burst from a batch job that would have been fine spread out.

Resolution

How to fix it

Back off exponentially
Retrying immediately extends the limit window on most limiters.
Batch instead of looping
Batch endpoints score many machines per call and are cheaper against the limit than one call each.
Use a key
Keyless access has much tighter limits than an authenticated one.

Normalization

What Forge does about it

This is a transport failure, so there is nothing for Forge to normalize: the reading never arrives. What Forge does is refuse to let the gap look like good data. The read-time dropout check flags a field that fell to zero and recovered as a communication glitch rather than a real measurement, and the stuck-sensor check fires when a value repeats for 20 consecutive readings — which is what a cached or last-known value looks like after a link drops. Forge does not retry or reconnect for you; that is your client's or your gateway's job.