xrpl-dev-portal/content/_snippets/string-number-formatting.md

XRP Ledger APIs generally use strings, rather than native JSON numbers, to represent numeric amounts of currency for both XRP and tokens. This protects against a loss of precision when using JSON parsers, which may automatically try to represent all JSON numbers in a floating-point format. Within the String value, the numbers are serialized in the same way as native JSON numbers:

• Base-10.
• Non-zero-prefaced.
• May contain . as a decimal point. For example, ½ is represented as 0.5. (American style, not European)
• Negative amounts start with the character -.
• May contain E or e to indicate being raised to a power of 10 (scientific notation). For example, 1.2E5 is equivalent to 1.2×10⁵, or 120000. Negative exponents are also possible.
• No comma (,) characters are used.