v3.26.1
Summary of Significant Accounting Policies - Concentration and risks (Details) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Concentration and risks      
Net revenues $ 21,712,720 $ 30,318,816 $ 31,976,268
Accounts receivable, net 1,802,899 2,860,537 2,334,607
Sales and marketing expenses (9,778,603) (15,056,063) (17,674,610)
Accounts payable 2,186,068 3,460,424  
Customer concentration risk | Revenue | Company A      
Concentration and risks      
Net revenues $ 2,876,424   $ 4,862,217
Concentration risk (as a percent) 13.25%   15.21%
Customer concentration risk | Revenue | Company B      
Concentration and risks      
Net revenues $ 8,959,954 $ 12,626,521 $ 4,453,331
Concentration risk (as a percent) 41.27% 41.65% 13.93%
Customer concentration risk | Revenue | Company C      
Concentration and risks      
Net revenues     $ 3,628,882
Concentration risk (as a percent)     11.35%
Customer concentration risk | Revenue | Company D      
Concentration and risks      
Net revenues $ 5,076,916 $ 6,801,056  
Concentration risk (as a percent) 23.38% 22.43%  
Customer concentration risk | Accounts receivable | Company A      
Concentration and risks      
Accounts receivable, net $ 192,954    
Concentration risk (as a percent) 10.70%    
Customer concentration risk | Accounts receivable | Company B      
Concentration and risks      
Accounts receivable, net $ 866,305 $ 1,311,926  
Concentration risk (as a percent) 48.05% 45.86%  
Customer concentration risk | Accounts receivable | Company D      
Concentration and risks      
Accounts receivable, net $ 339,680 $ 393,620  
Concentration risk (as a percent) 18.84% 13.76%  
Customer concentration risk | Accounts receivable | Company E      
Concentration and risks      
Accounts receivable, net   $ 307,987  
Concentration risk (as a percent)   10.77%  
Vendor concentration risk | Sales and marketing expenses | Company A      
Concentration and risks      
Sales and marketing expenses $ (5,799,815) $ (4,993,977) $ (8,345,027)
Concentration risk (as a percent) 59.31% 33.17% 47.21%
Vendor concentration risk | Sales and marketing expenses | Company F      
Concentration and risks      
Sales and marketing expenses $ (2,763,155) $ (8,497,678) $ (3,349,826)
Concentration risk (as a percent) 28.26% 56.44% 18.95%
Vendor concentration risk | Sales and marketing expenses | Company G      
Concentration and risks      
Sales and marketing expenses     $ (2,098,906)
Concentration risk (as a percent)     11.88%
Vendor concentration risk | Accounts payable | Company A      
Concentration and risks      
Accounts payable $ 703,870 $ 859,102  
Concentration risk (as a percent) 32.20% 24.83%  
Vendor concentration risk | Accounts payable | Company F      
Concentration and risks      
Accounts payable $ 562,871 $ 1,370,430  
Concentration risk (as a percent) 25.75% 39.60%  
Vendor concentration risk | Accounts payable | Company H      
Concentration and risks      
Accounts payable $ 399,421 $ 390,553  
Concentration risk (as a percent) 18.27% 11.29%