Contracts

Create, test, and manage Clarity smart contracts in Scaffold Stacks with stacksdapp add, check, and deploy — includes SIP-010 and SIP-009 templates.

Add, test, and deploy Clarity contracts with auto-generated TypeScript bindings. New projects default to Clarity 6 (epoch 4.0).

Contents

• Creating contracts
• Sample contract
• SIP token templates
• Contract requirements
• Key concepts
• Testing contracts

Creating contracts

Use the CLI to add new contracts to your project:

# Create a blank contract (Clarity 6 by default)
stacksdapp add message

# Create a SIP-010 fungible token
stacksdapp add my-token --template sip010

# Create a SIP-009 NFT
stacksdapp add my-nft --template sip009

# Legacy Clarity 5 contract
stacksdapp add legacy-token --template sip010 --clarity-version 5

Each command creates the .clar file, a Vitest test, updates Clarinet.toml with the correct epoch, adds trait requirements for SIP templates, and regenerates TypeScript bindings.

Sample contract

The default scaffolded counter contract demonstrates data storage and public/read-only functions:

;; counter.clar scaffolded by scaffold-stacks

(define-data-var counter uint u0)

(define-read-only (get-count)
  (ok (var-get counter)))

(define-public (increment)
  (begin
    (var-set counter (+ (var-get counter) u1))
    (ok (var-get counter))))

(define-public (decrement)
  (begin
    (asserts! (> (var-get counter) u0) (err u1))
    (var-set counter (- (var-get counter) u1))
    (ok (var-get counter))))

(define-public (reset)
  (begin
    (var-set counter u0)
    (ok u0)))

SIP token templates

SIP-010 and SIP-009 templates implement all required trait functions. They ship without (impl-trait …) so testnet deploy succeeds.

Network	impl-trait	Notes
Testnet	Omit	No standard trait contract deployed on testnet
Mainnet	Required for wallet listing	Uncomment the mainnet line in the template before deploy
Simnet / tests	Omit	Clarinet requirement pulls mainnet trait for type-checking

Never use bare trait names like (impl-trait 'sip-010-trait). Use the full mainnet path or omit for testnet. See the comment in each SIP template for the exact mainnet line.

Mainnet trait addresses:

Standard	impl-trait (mainnet only)
SIP-010	'SP3FBR2AGK5H9QBDH3EEN6DF8EK8JY7RX8QJ5SVTE.sip-010-trait-ft-standard.sip-010-trait
SIP-009	'SP2PABAF9FTAJYNFZH93XENAJ8FVY99RRM50D2JG9.nft-trait

Contract requirements

For contracts that depend on external contracts (like sBTC), add requirements:

cd contracts

clarinet requirements add SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-deposit

SIP templates automatically add trait requirements to Clarinet.toml for simnet type-checking.

Key concepts

sBTC Integration

Contracts using sBTC require the sBTC contract as a dependency:

• Uses restrict-assets? for post-conditions
• Transfers sBTC using the official token contract

Data Storage

• Maps: Store structured data with metadata
• Data variables: Track counters and global state
• Constants: Define immutable values

Access Control

• CONTRACT_OWNER for privileged operations
• asserts! for authorization checks
• tx-sender vs contract-caller for security

Read-Only Functions

• Query contract state without transactions
• Return Optional types for safe lookups

See SIP standards for trait tables, hook examples, and impl-trait rules.

Testing contracts

Write tests in contracts/tests/ using the Clarinet SDK with the clarinet Vitest environment:

import { describe, expect, it } from "vitest";
import { Cl } from "@stacks/transactions";

const accounts = simnet.getAccounts();
const deployer = accounts.get("deployer")!;

describe("counter", () => {
  it("increments", () => {
    const { result } = simnet.callPublicFn("counter", "increment", [], deployer);
    expect(result).toBeOk(Cl.uint(1));
  });
  it("get-count returns current value", () => {
    simnet.callPublicFn("counter", "increment", [], deployer);
    const { result } = simnet.callReadOnlyFn("counter", "get-count", [], deployer);
    expect(result).toBeOk(Cl.uint(1));
  });
});

stacksdapp test

Full patterns, ABI caching, and frontend Vitest coverage live in Testing.