No. Change FLAC Speed is free without an account, and nothing is added to the audio. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.
דער איבערזעצער אויף דער וועבזײַט װײַזט אױף אַודיאָ־פֿאָרמאַטירונגען װי MP3, WAV, FLAC, M4A, OGG און Opus, אַזוי די אױסגאַבע־פֿאָרמאַטירונג איז אַ באַשלוס װאָס דו קענסט איבערלאָזן ביז צום סוף, ניט צום אָנהייב Doing that after Change FLAC Speed rather than before means the encode happens once, on the file you actually settled on, instead of twice.
איז Change FLAC Speed דאָ דער זעלבער מכשיר װאָס די שוועסטער־סײַטן װײַזן?
No account is needed. Uploads and results are kept for about 24 hours, which leaves time to download the result, and are then deleted automatically; nobody reads, lists or indexes them. Several files in one job need a paid plan.