Basuki Tjahaja Purnama -- the first Christian to govern the capital in more than 50 years -- sparked anger in the Muslim-majority country when he quoted a verse from the Koran while campaigning ahead of elections for the Jakarta governorship.
The high-profile case against Purnama, better known by his nickname Ahok, has captivated attention in Indonesia, and fanned concerns about hardliners pushing their agenda in the nation of 255 million.
Outside the court, hundreds of protesters chanting slogans including "God is Great".
"We Muslims demand Ahok to be jailed or punished as severely as possible," said Suyono, who like many Indonesians go by one name.
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Purnama remains a candidate for re-election in February, though he could be jailed for a maximum of five years if found guilty.
He had been a favourite to win but the lawsuit has seen polls turn against him.
Almost all blasphemy cases in Indonesia have resulted in convictions and rights groups fear the case is eroding the country's reputation for tolerance and diversity.
The trial has been adjourned until January 3.