Donald Trump may have mastered Twitter and Facebook for his presidential campaign — but his debut on the social media site Reddit Wednesday could have been bottled as a sure cure for insomnia.

Trump replied to a handful of questions posted by users on one of the sites “Ask Me Anything” segments, but offered little more than his stock responses and vague policy statements on the usually free-for-all forum.

“Voter fraud is always a serious concern and authorities must be vigilant from keeping those from voting that are not authorized to do so,” he replied to a question suggesting that Hillary Clinton would try to steal the election.

“Honestly I think NASA is wonderful! America has always led the world in space exploration,” he said about a question of what role NASA could play in making America great again.

He took aim at “Crooked Hillary” in several responses.

“Keeping Crooked Hillary Clinton out of the White House!” was his answer to a question about how he would cut wasteful government spending.

“Crooked Hillary Clinton will not do press conferences,” he said, adding that she had too many skeletons to hide to talk to the media.

The GOP nominee also pledged to repeal Obamacare and support the police — and slammed the press for being dishonest in replies that seemed to be slowed by WiFi issues, as Trump was answering from his plane on the way from Wisconsin to a rally in Ohio.

The AMA, as the sessions are called, was heavily moderated by Reddit staffers to prevent crank questions or offensive answers.

The pro-Trump “subreddit /r/The_Donald” has become a haven for many of Trump’s tech-savvy supporters, according to the website wired.com.

The Trump subreddit is the third-most active on Reddit — even more popular than the one for the Pokemon Go game, wired.com said — with more than 180,000 subscribers compared to about 21,000 for Hillary Clinton’s subreddit.

Redditors, the people who edit the site, call Trump “God Emperor.”

And they insist the GOP nominee attracts a broader audience than the less-educated white males who make up much of his base.

“We know for a fact that our community is extremely socially libertarian—and culturally as well,” one moderator, who goes by the name Viking83, told wired.com.

Many of those who commented seemed happy with Trump’s performance.

“There is nothing better than being graced by America’s future POTUS. Your [sic] no bulls–t, anti-pc, brutally honest statements in your campaign is [sic] a huge breath of fresh air. WE LOVE YOU TRUMP,” posted one.