juice

Juice Accounting

Juice prices computation and bandwidth. It is a flow: consumed and paid per transaction, never held. Storage is priced separately — see the memory skill.

Normative spec: https://docs.convex.world/docs/cad/juice.

The Calculation

Juice Fees     = Juice Consumed × Juice Price
Juice Consumed = Transaction Size Cost + Σ(cost of each operation executed)

Transaction Size Cost = TRANSACTION_PER_BYTE × storage size of the transaction

TRANSACTION_PER_BYTE is 20, so the size of the submitted transaction is itself a cost, independent of what it does. Compact transaction source is cheaper source.

Allowance

Every transaction carries a juice allowance:

• Specified by the user, or the maximum available if unspecified
• Capped at 10,000,000, bounding the cost of any single transaction
• May not exceed what the origin account can actually pay

On a :JUICE failure the origin is charged the full allowance and every state change is rolled back. Running out is not free — it is the most expensive way for a transaction to fail. When execution cost is uncertain, estimate against a local network before submitting.

Price

Juice price lives in the CVM state and is readable from CVM code as *juice-price*. The genesis price is 10 (Constants.INITIAL_JUICE_PRICE, set 2024 and what Protonet runs; CAD007 was aligned to match in #697). A live network's price is whatever its genesis state carries.

CAD007 also specifies dynamic pricing — the price rising under sustained load and decaying towards a hard floor of 1 — but this is not yet implemented: nothing updates *juice-price* after genesis, so treat the price as constant today. Implementation is tracked in #408 / #423.

Dynamic pricing is the intended cryptoeconomic defence: sustaining an attack would mean paying exponentially rising prices, so a burst while prices are low could only delay confirmation, not exclude legitimate transactions.

Pricing New Operations

If you add a CVM op or runtime function, it needs a juice cost.

• Every op MUST have a fixed positive cost — nothing executes free.
• An op whose work scales with input size MUST have a cost that scales too.
• The CVM MUST check sufficient juice before performing O(n) work, and raise :JUICE if it is not there.

That ordering is a security property, not an optimisation. If an attacker can trigger O(n) work having committed less than O(n) of juice, the asymmetry is a denial-of-service vector. Cost should track an upper bound on compute time, storage size or bandwidth — whichever dominates.

Relationship to Memory

A transaction short of memory allowance can buy memory from the pool using its remaining juice — so juice exhaustion can surface as a :MEMORY failure and vice versa. See the memory skill for that interaction.