The visa guide states 3 Letters of Recommendation are necessary.
I have seen some sites stating that at least 3 Letter of Recommendation is required, however suggestion is to collect as much as possible, let say 4-5 Letters. Here is the original quote:
“You must provide at least 3 letters from 3 different referents. We highly recommend you to prepare 4−5 letters, because Tech Nation often dismisses recommendation letters due to noncompliance with the criteria”
Is it possible to submit more than 3 letters of recommendation?
Don’t use any other site except tech nation website
Yes, but the form will only let you submit 3, the others will count towards your 10 pieces of evidence. Quality matters way more than quantity in this case though, if your 3 recommendations are already good (and from different companies), I would use space for pieces of evidence instead, not more recommendations.
That said, I did submit 5 letters of recommendations for my endorsement application, but only because the two additional recommenders highlighted my work towards each of the two optional criteria (whereas my main 3 highlighted the mandatory criteria more). See details and reasoning on my application here.