# Writing Simplicity Programs with SimplicityHL

**URL:** <https://delvingbitcoin.org/t/writing-simplicity-programs-with-simplicityhl/1900>\
**Category:** Protocol Design\
**Tags:** simplicity\
**Created:** [August 4, 2025, 7:19pm UTC](https://delvingbitcoin.org/t/writing-simplicity-programs-with-simplicityhl/1900 "2025-08-04T19:19:02Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![niftynei](https://delvingbitcoin.org/letter_avatar_proxy/v4/letter/n/c77e96/32.png) [@niftynei](https://delvingbitcoin.org/u/niftynei)\
**Post date:** [August 5, 2025, 3:32pm UTC](https://delvingbitcoin.org/t/writing-simplicity-programs-with-simplicityhl/1900/2 "2025-08-05T15:32:01Z")

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Nice. A reverse dutch auction for fees on a transaction is such a neat idea.

This is my first time really looking at a simplicityHL contract, and it’s surprising me how much it resembles “normal code”.

Am I right in reading this as including a custom sighash implementation? That’s a neat trick.

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