QELT Smart Contract Verification Skill

The QELT Mainnet Indexer provides production-grade contract verification via REST API. Supports 500+ Solidity versions, constructor arguments, library linking, multi-file contracts (75+ files), viaIR compilation, and automatic EVM version detection.

API Base: https://mnindexer.qelt.ai Rate Limit: 10 verification submissions per hour per IP Timeout per job: 600 seconds (10 minutes) Status polling: Unlimited — poll every 3–5 seconds freely

Safety

• Do not submit source code containing private keys or secrets.
• Verification is permanent — source becomes public once verified.
• Always check if already verified before submitting (saves rate limit quota).
• status: "completed" does NOT mean verified — always check result.verified === true.
• Status polling is unlimited — do not re-submit while a job is still processing.

Procedure

1. Check if Already Verified (Do This First)

curl -fsSL "https://mnindexer.qelt.ai/api/v2/contracts/0xCONTRACT/verification"

If "verified": true → return existing source/ABI to user, no submission needed.

2. Submit Single-File Contract

curl -fsSL -X POST "https://mnindexer.qelt.ai/api/v1/verification/submit" \
  -H "Content-Type: application/json" \
  -d '{
    "address": "0xCONTRACT",
    "sourceCode": "// SPDX-License-Identifier: MIT\npragma solidity ^0.8.20;\n...",
    "compilerVersion": "0.8.20",
    "contractName": "MyContract",
    "optimizationUsed": true,
    "runs": 200,
    "evmVersion": "shanghai",
    "constructorArguments": "0x000...",
    "libraries": {}
  }'

Response: { "success": true, "jobId": "uuid", "statusUrl": "/api/v1/verification/status/uuid" }

3. Submit Multi-File Contract (with imports)

For contracts using OpenZeppelin or any import statements:

curl -fsSL -X POST "https://mnindexer.qelt.ai/api/v1/verification/submit-multi" \
  -H "Content-Type: application/json" \
  -d '{
    "address": "0xCONTRACT",
    "compilerVersion": "v0.8.17+commit.8df45f5f",
    "contractName": "MyToken",
    "optimizationUsed": true,
    "runs": 200,
    "viaIR": true,
    "evmVersion": "london",
    "mainFile": "contracts/MyToken.sol",
    "sourceFiles": {
      "contracts/MyToken.sol": "pragma solidity ^0.8.17; ...",
      "@openzeppelin/contracts/token/ERC20/ERC20.sol": "..."
    }
  }'

4. Poll Status (Unlimited)

curl -fsSL "https://mnindexer.qelt.ai/api/v1/verification/status/JOB_ID"

States: pending → processing → completed / failed

⚠️ After "completed", always verify result.verified === true:

{
  "status": "completed",
  "result": { "verified": true, "abi": [...] }
}

verified: false with status: "completed" = bytecode mismatch.

5. Get Compiler Versions

curl -fsSL "https://mnindexer.qelt.ai/api/v2/verification/compiler-versions"

6. Get EVM Versions

curl -fsSL "https://mnindexer.qelt.ai/api/v2/verification/evm-versions"

EVM Version Selection

Solidity Range	EVM Version
0.5.14 – 0.8.4	istanbul
0.8.5	berlin
0.8.6 – 0.8.17	london
0.8.18 – 0.8.19	paris
0.8.20 – 0.8.23	shanghai
0.8.24+	cancun

QELT Mainnet runs EVM Cancun — use cancun for Solidity 0.8.24+.

Rate Limits

Endpoint	Limit
POST /api/v1/verification/submit	10 req/hour per IP
POST /api/v1/verification/submit-multi	10 req/hour per IP
GET /api/v1/verification/status/:jobId	Unlimited
All other GET endpoints	Not rate limited

Rate limit headers: X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, Retry-After.

Common Errors

Symptom	Likely Cause	Fix
verified: false (completed)	Wrong compiler/optimization/args	Match exact deployment settings
HTTP 429	Rate limited	Wait Retry-After seconds (usually 3600)
status: "failed"	Compilation error	Check message field
Timeout at 600s	Large contract + viaIR	Normal; job still finishes

Best Practices

1. Check before submit — use GET /api/v2/contracts/:address/verification first
2. Use /submit-multi for any contract with import statements
3. Include "viaIR": true if compiled with viaIR: true in hardhat config
4. Poll every 3–5 seconds — do not re-submit a pending job

Developer Tools

Hardhat Plugin: npm install --save-dev @qelt/hardhat-verify@latest

npx hardhat qelt:verify --network qelt 0xCONTRACT_ADDRESS

CLI Tool: npm install -g qelt-verify → qelt-verify verify 0x... ./Contract.sol --compiler-version 0.8.20 --optimize