You can use a Factoring company (someone who purchases invoices).

And likely they'll require some sort of seasoning of recurring payments before purchasing.

You can go for Angel capitol + will have to give up a big chunk of income.

If possible, write your own bridge loans by writing balance transfer checks on your credit cards.

Usually this costs 1%-1.5% of check's value, so way cheaper than any other option + instant + you keep 100% ownership of your company.