Indonesia
Business income — a flat 0.5% final tax on gross (if turnover ≤ IDR 4.8bn) or progressive 5–35% on net. Self-assessed because a foreign firm won't withhold. USDC is income at IDR value on receipt.
Business/professional income (penghasilan dari usaha/pekerjaan bebas). With a foreign payer, the individual self-assesses.
Either a final 0.5% on gross turnover under the UMKM/MSME scheme (turnover ≤ IDR 4.8bn) OR progressive 5–35% on net income.
BPJS participation exists but is not a payroll-style tax on foreign-source contractor income.
UMKM final 0.5% scheme is the key simplified option (turnover ≤ IDR 4.8bn, limited years). Above that, register as PKP, charge 11–12% VAT, use normal rates.
USDC is income at IDR value on receipt; Indonesia's separate 0.1–0.2% final crypto-transaction tax mainly applies to exchange disposals.