user934: I have a parameterized contract that includes a POSIXTime as a field called startTime served via PAB.
What is the appropriate stringified HTTP payload to indicate a date with time such as the 25th of September 2021 at noon (no timezone?).

user935: I had troubles making POSIXTime a part of JSON payload, you can just unwrap the Integer inside and use it instead.
Anyway, JSON serialization is implemented here, you can check that instance for details.
If you need to convert POSIXTime to standard time format, something like this function would be useful.

934: <p>I have a parameterized contract that includes a POSIXTime as a field called startTime served via PAB.</p>
<p>What is the appropriate stringified HTTP payload to indicate a date with time such as the 25th of September 2021 at noon (no timezone?).</p>
 935: <p>I had <a href="https://github.com/input-output-hk/plutus/issues/3979" rel="nofollow noreferrer">troubles</a> making <code>POSIXTime</code> a part of JSON payload, you can just unwrap the <code>Integer</code> inside and use it instead.</p>
<p>Anyway, JSON serialization is implemented <a href="https://github.com/input-output-hk/plutus/blob/a3697f0ca6c51e8415a1433aa17159ab3986a4f5/plutus-ledger-api/src/Plutus/V1/Ledger/Time.hs#L66" rel="nofollow noreferrer">here</a>, you can check that instance for details.</p>
<p>If you need to convert <code>POSIXTime</code> to standard time format, something like this <a href="https://hackage.haskell.org/package/time-1.12/docs/Data-Time-Clock-POSIX.html#v:posixSecondsToUTCTime" rel="nofollow noreferrer">function</a> would be useful.</p>
