OET interlinear YHN (JHN) 1:27

uW Translation Notes:

Note 1 topic: figures-of-speech / explicit

ὁ ὀπίσω μου ἐρχόμενος

the_‹one› after (Some words not found in SR-GNT: ὁ ὀπίσω μού ἐρχόμενος οὗ οὐκ εἰμί ἐγώ ἄξιος ἵνα λύσω αὐτοῦ τόν ἱμάντα τοῦ ὑποδήματος)

John is speaking about Jesus. The phrase coming after me means that John’s ministry has already started and Jesus’ ministry will start later. You could include this information if that would be helpful to your readers. Alternate translation: [the one who starts his ministry after I have done so]

Note 2 topic: figures-of-speech / metaphor

μου & οὗ οὐκ εἰμὶ ἐγὼ ἄξιος, ἵνα λύσω αὐτοῦ τὸν ἱμάντα τοῦ ὑποδήματος

(Some words not found in SR-GNT: ὁ ὀπίσω μού ἐρχόμενος οὗ οὐκ εἰμί ἐγώ ἄξιος ἵνα λύσω αὐτοῦ τόν ἱμάντα τοῦ ὑποδήματος)

Untying sandals was the work of a slave or servant. John the Baptist uses this expression figurative to refer to the most unpleasant work of a servant. If it would be helpful in your language, you could express the meaning plainly. Alternate translation: [me. I am not even worthy to untie the strap of his sandal] or [me, whom I am not worthy to serve in even the most unpleasant way]