Contracts Act (Cap. 53): Primary legislation governing contract formation, including requirements for consideration, capacity to contract, and free consent provisions. Essential for the basic validity of the Promise to Pay agreement.

Limitation Act (Cap. 163): Sets time limits for enforcement of contractual rights, particularly the 6-year limitation period for debt collection. Critical for enforcement timeline provisions.

Money-lenders Act (Cap. 188): Regulates lending activities, including licensing requirements and interest rate restrictions. Applicable if the promise to pay involves a loan from a moneylender.

Interest Act (Cap. 173): Contains regulations regarding interest rates and rules about compound interest. Essential for structuring interest payment terms.

Civil Law Act (Cap. 43): Governs enforceability of contracts and rules regarding contractual damages. Provides framework for remedy provisions.

Rules of Court: Outlines procedures for enforcement and available legal remedies. Important for understanding enforcement mechanisms.

Consumer Protection (Fair Trading) Act: Provides protection for consumer transactions and regulations against unfair practices. Applicable if the agreement involves consumer transactions.

Electronic Transactions Act: Governs electronic execution of contracts and requirements for electronic signatures. Relevant if the contract will be executed electronically.

Common Law Principles: Established legal principles from case law regarding debt agreements and promise to pay contracts in Singapore's legal system.

Stamp Duties Act: Requirements for stamp duty payment on certain types of agreements. May be applicable depending on the nature and value of the promise to pay.