Simplicity - Revision history

NotATether: Add Language model and Relation to Tapscript sections

2026-09-13T07:30:36Z

Add Language model and Relation to Tapscript sections

← Older revision		Revision as of 07:30, 13 September 2026
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	Simplicity is intended eventually to appear as a versioned leaf alongside Script inside [[Taproot]] trees on Bitcoin. As of the Liquid Network deployment, it runs on that sidechain's consensus rules rather than on Bitcoin mainnet. Jets provide optimized implementations of recognized subexpressions such as cryptographic primitives. Higher-level languages such as SimplicityHL compile down to Simplicity. Mainnet Bitcoin would need a consensus definition of the leaf version, cost model, and jet set before transactions could execute Simplicity programs under Bitcoin consensus.		Simplicity is intended eventually to appear as a versioned leaf alongside Script inside [[Taproot]] trees on Bitcoin. As of the Liquid Network deployment, it runs on that sidechain's consensus rules rather than on Bitcoin mainnet. Jets provide optimized implementations of recognized subexpressions such as cryptographic primitives. Higher-level languages such as SimplicityHL compile down to Simplicity. Mainnet Bitcoin would need a consensus definition of the leaf version, cost model, and jet set before transactions could execute Simplicity programs under Bitcoin consensus.

			== Language model ==

	Combinators include pairing, unit values, sums, and products that build expressions without mutable state. Because there is no unbounded looping construct, termination and an upper bound on Bit Machine steps can be derived from the program text before execution. That property is the main contrast with general-purpose smart-contract VMs that rely on runtime gas metering alone.		Combinators include pairing, unit values, sums, and products that build expressions without mutable state. Because there is no unbounded looping construct, termination and an upper bound on Bit Machine steps can be derived from the program text before execution. That property is the main contrast with general-purpose smart-contract VMs that rely on runtime gas metering alone.
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	Witnesses for Simplicity spends carry the program and its input data in a form the Bit Machine can evaluate under the leaf's cost budget. A program that exceeds static weight or step limits is rejected before validation can waste unbounded work. Liquid's deployment is therefore a live test of jets and tooling, not evidence that Bitcoin consensus already accepts the same leaf version.		Witnesses for Simplicity spends carry the program and its input data in a form the Bit Machine can evaluate under the leaf's cost budget. A program that exceeds static weight or step limits is rejected before validation can waste unbounded work. Liquid's deployment is therefore a live test of jets and tooling, not evidence that Bitcoin consensus already accepts the same leaf version.

			== Relation to Tapscript ==

	Compared with Tapscript, Simplicity aims for a smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continues on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.		Compared with Tapscript, Simplicity aims for a smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continues on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.


	== See also ==		== See also ==

NotATether: Remove duplicate paragraph and tighten cost-limit wording

2026-09-13T07:27:39Z

Remove duplicate paragraph and tighten cost-limit wording

← Older revision		Revision as of 07:27, 13 September 2026
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	Jets are consensus-recognized shortcuts. A jet matches a Simplicity expression and evaluates it with a fast native implementation while charging a predetermined cost. Cryptographic hashes and signature checks are typical jet candidates. Without a mainnet soft fork that defines leaf version, jets, and weights, Simplicity programs remain consensus-invalid on Bitcoin even if they run on Liquid.		Jets are consensus-recognized shortcuts. A jet matches a Simplicity expression and evaluates it with a fast native implementation while charging a predetermined cost. Cryptographic hashes and signature checks are typical jet candidates. Without a mainnet soft fork that defines leaf version, jets, and weights, Simplicity programs remain consensus-invalid on Bitcoin even if they run on Liquid.

	Witnesses for Simplicity spends carry the program and its input data in a form the Bit Machine can evaluate under the leaf's cost budget. A program that exceeds static weight or step limits is rejected before it can ~~loop the network in validation~~. Liquid's deployment is therefore a live test of jets and tooling, not evidence that Bitcoin consensus already accepts the same leaf version.		Witnesses for Simplicity spends carry the program and its input data in a form the Bit Machine can evaluate under the leaf's cost budget. A program that exceeds static weight or step limits is rejected before validation can waste unbounded work. Liquid's deployment is therefore a live test of jets and tooling, not evidence that Bitcoin consensus already accepts the same leaf version.

	Compared with Tapscript, Simplicity aims for smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continue on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.

	Compared with Tapscript, Simplicity aims for a smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continues on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.		Compared with Tapscript, Simplicity aims for a smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continues on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.

NotATether: Expand See also links

2026-09-13T07:26:54Z

Expand See also links

← Older revision		Revision as of 07:26, 13 September 2026
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	* [[Sidechain]]		* [[Sidechain]]
	* [[Softfork]]		* [[Softfork]]
			* [[OP VAULT]]

	== External links ==		== External links ==

NotATether: Add Tapscript contrast and research status

2026-09-13T07:26:52Z

Add Tapscript contrast and research status

← Older revision		Revision as of 07:26, 13 September 2026
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	Compared with Tapscript, Simplicity aims for smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continue on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.		Compared with Tapscript, Simplicity aims for smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continue on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.

			Compared with Tapscript, Simplicity aims for a smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continues on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.

	== See also ==		== See also ==

NotATether: Add Tapscript contrast and research status

2026-09-13T07:26:50Z

Add Tapscript contrast and research status

← Older revision		Revision as of 07:26, 13 September 2026
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	Witnesses for Simplicity spends carry the program and its input data in a form the Bit Machine can evaluate under the leaf's cost budget. A program that exceeds static weight or step limits is rejected before it can loop the network in validation. Liquid's deployment is therefore a live test of jets and tooling, not evidence that Bitcoin consensus already accepts the same leaf version.		Witnesses for Simplicity spends carry the program and its input data in a form the Bit Machine can evaluate under the leaf's cost budget. A program that exceeds static weight or step limits is rejected before it can loop the network in validation. Liquid's deployment is therefore a live test of jets and tooling, not evidence that Bitcoin consensus already accepts the same leaf version.

			Compared with Tapscript, Simplicity aims for smaller analysis surface and optional formal proofs of contract properties. Application developers still need audited jets and careful handling of any residual Script leaves in the same Taproot tree. Research continue on how covenants and vaults would be expressed as Simplicity programs once a mainnet leaf is defined.

	== See also ==		== See also ==

NotATether: Add witness cost model and Liquid caveat

2026-09-13T07:26:48Z

Add witness cost model and Liquid caveat

← Older revision		Revision as of 07:26, 13 September 2026
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	Jets are consensus-recognized shortcuts. A jet matches a Simplicity expression and evaluates it with a fast native implementation while charging a predetermined cost. Cryptographic hashes and signature checks are typical jet candidates. Without a mainnet soft fork that defines leaf version, jets, and weights, Simplicity programs remain consensus-invalid on Bitcoin even if they run on Liquid.		Jets are consensus-recognized shortcuts. A jet matches a Simplicity expression and evaluates it with a fast native implementation while charging a predetermined cost. Cryptographic hashes and signature checks are typical jet candidates. Without a mainnet soft fork that defines leaf version, jets, and weights, Simplicity programs remain consensus-invalid on Bitcoin even if they run on Liquid.

			Witnesses for Simplicity spends carry the program and its input data in a form the Bit Machine can evaluate under the leaf's cost budget. A program that exceeds static weight or step limits is rejected before it can loop the network in validation. Liquid's deployment is therefore a live test of jets and tooling, not evidence that Bitcoin consensus already accepts the same leaf version.

	== See also ==		== See also ==

NotATether: Expand See also links

2026-09-13T07:22:40Z

Expand See also links

← Older revision		Revision as of 07:22, 13 September 2026
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	* [[Script]]		* [[Script]]
	* [[Taproot]]		* [[Taproot]]
			* [[Sidechain]]
			* [[Softfork]]

	== External links ==		== External links ==

NotATether: Add jets and mainnet soft-fork requirement

2026-09-13T07:22:39Z

Add jets and mainnet soft-fork requirement

← Older revision		Revision as of 07:22, 13 September 2026
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	Combinators include pairing, unit values, sums, and products that build expressions without mutable state. Because there is no unbounded looping construct, termination and an upper bound on Bit Machine steps can be derived from the program text before execution. That property is the main contrast with general-purpose smart-contract VMs that rely on runtime gas metering alone.		Combinators include pairing, unit values, sums, and products that build expressions without mutable state. Because there is no unbounded looping construct, termination and an upper bound on Bit Machine steps can be derived from the program text before execution. That property is the main contrast with general-purpose smart-contract VMs that rely on runtime gas metering alone.

			Jets are consensus-recognized shortcuts. A jet matches a Simplicity expression and evaluates it with a fast native implementation while charging a predetermined cost. Cryptographic hashes and signature checks are typical jet candidates. Without a mainnet soft fork that defines leaf version, jets, and weights, Simplicity programs remain consensus-invalid on Bitcoin even if they run on Liquid.

	== See also ==		== See also ==

NotATether: Add combinator model and static bounds

2026-09-13T07:22:37Z

Add combinator model and static bounds

← Older revision		Revision as of 07:22, 13 September 2026
Line 2:		Line 2:

	Simplicity is intended eventually to appear as a versioned leaf alongside Script inside [[Taproot]] trees on Bitcoin. As of the Liquid Network deployment, it runs on that sidechain's consensus rules rather than on Bitcoin mainnet. Jets provide optimized implementations of recognized subexpressions such as cryptographic primitives. Higher-level languages such as SimplicityHL compile down to Simplicity. Mainnet Bitcoin would need a consensus definition of the leaf version, cost model, and jet set before transactions could execute Simplicity programs under Bitcoin consensus.		Simplicity is intended eventually to appear as a versioned leaf alongside Script inside [[Taproot]] trees on Bitcoin. As of the Liquid Network deployment, it runs on that sidechain's consensus rules rather than on Bitcoin mainnet. Jets provide optimized implementations of recognized subexpressions such as cryptographic primitives. Higher-level languages such as SimplicityHL compile down to Simplicity. Mainnet Bitcoin would need a consensus definition of the leaf version, cost model, and jet set before transactions could execute Simplicity programs under Bitcoin consensus.

			Combinators include pairing, unit values, sums, and products that build expressions without mutable state. Because there is no unbounded looping construct, termination and an upper bound on Bit Machine steps can be derived from the program text before execution. That property is the main contrast with general-purpose smart-contract VMs that rely on runtime gas metering alone.

	== See also ==		== See also ==

NotATether: create Simplicity stub (combinator language, Liquid not mainnet)

2026-09-06T03:27:49Z

create Simplicity stub (combinator language, Liquid not mainnet)

New page

'''Simplicity''' is a typed, combinator-based functional blockchain language designed by Russell O'Connor as an alternative to Bitcoin [[Script]] and Tapscript. Programs are built from a small set of combinators without loops or recursion. The language is deliberately not Turing complete, yet it can express any finitary function. Formal denotational semantics in a proof assistant and an operational cost model called the Bit Machine support static resource bounds and machine-checkable reasoning about contract behavior.

Simplicity is intended eventually to appear as a versioned leaf alongside Script inside [[Taproot]] trees on Bitcoin. As of the Liquid Network deployment, it runs on that sidechain's consensus rules rather than on Bitcoin mainnet. Jets provide optimized implementations of recognized subexpressions such as cryptographic primitives. Higher-level languages such as SimplicityHL compile down to Simplicity. Mainnet Bitcoin would need a consensus definition of the leaf version, cost model, and jet set before transactions could execute Simplicity programs under Bitcoin consensus.

== See also ==

* [[Script]]
* [[Taproot]]

== External links ==

* [https://arxiv.org/abs/1711.03028 Simplicity: A New Language for Blockchains (paper)]
* [https://github.com/BlockstreamResearch/Simplicity BlockstreamResearch/Simplicity]
* [https://simplicity-lang.org/ Simplicity language site]

[[Category:Technical]]