How can I deal with my imposter syndrome after getting up-leveled?

• I consider Twitter a top-tier company at the same level as FAANG, so I'll say what I've said to so many of my mentees across my time at Meta in particular: These companies spend literally thousands of hours across the world's best engineers crafting air-tight interview processes designed to weed out lackluster talent and truly hire the best. If Twitter believes you deserve this, you 99.9% deserve it. It is just near statistically impossible that you're not actually at this level and managed to "trick" the interview, especially with something as deliberate as a senior up-level.
• At the end of the day, it's crucial to just focus on real problems and not create problems in your own head, turning yourself into your own worst enemy. Just focus on doing good work and getting feedback. If you are truly doing good work, you will get good feedback, which will help alleviate the imposter syndrome.
• You should only worry about your performance if it's concretely on your performance review, either through an actual bad review or dire feedback from your manager/peers that you are not on track for a good rating. If that's not the case, keep on doing your thing as mentioned before: Do the best work you can and build deep relationships to get real feedback, so you can regularly calibrate yourself.

Related resources:

• "I've felt imposter syndrome from seeing super talented peers - How do I deal with this?"
• "How can I bridge my confidence gap to put myself out there more and ask for help more aggressively?"