Amounts and precision

JavaScript numbers can't represent values like 0.1 + 0.2 exactly. Nexlm never uses floats for money on the server.

Minor units

Currency	Minor unit	Decimals
XLM	stroop (0.0000001)	7
NGN	kobo (0.01)	2

server/src/lib/amount.js converts decimal strings to BigInt minor units and back:

toStroops('123.4567891')     // 1234567891n
fromStroops(1234567891n)     // '123.4567891'
addXlm('0.1', '0.2')         // '0.3'
compareXlm('10', '9.9999999') // 1
ngnTotal('100', '520.25')    // '52025.00'

The helpers also accept Prisma Decimal objects (anything with toFixed).

Rounding

ngnTotal(xlm, rate) multiplies stroops by kobo and rounds half-up to the nearest kobo:

kobo = (stroops × rateKobo + 5_000_000) ÷ 10_000_000

Validation

• XLM inputs: ^\d+(\.\d{1,7})?$ and greater than zero
• NGN rates: ^\d+(\.\d{1,2})?$ and greater than zero

Values with too many decimals are rejected rather than rounded.

Stellar SDK

Stellar operations take amounts as strings with at most 7 decimals. Always pass fromStroops(toStroops(value)) rather than String(decimal) — Decimal#toString() can produce exponent notation for tiny values.

Client

The client uses floats only for display estimates (estimateNgn). The server's ngnAmount is authoritative.