No. The code encodes your text or URL directly, so it works forever with no dependency on us. Many "free" QR generators encode a link to their own tracking domain and redirect from there — which means your printed code stops working the day that service shuts down or starts charging. Always check that a generated QR scans to your actual URL.
Which error-correction level should I choose?
M is the right default. Choose H if the code will be printed small, on a curved surface, or with a logo over the centre — it can lose ~30% of its modules and still decode. Choose L only when you need the fewest possible modules for a long payload.
Why will my custom-coloured QR code not scan?
Almost always insufficient contrast, or inversion. Scanners expect a dark foreground on a light background with strong contrast; light-on-dark and low-contrast pastel combinations fail on many readers. Test on more than one phone before printing.
How much data fits in a QR code?
Up to 2,953 bytes at the largest symbol version and lowest error correction — but that produces a dense grid that needs a good camera and a large print. In practice, keep payloads under a few hundred characters; for anything longer, encode a short URL that points to the content.