Authenticate to the Venice API with a Bearer API key or with an x402 / SIWE wallet. Covers header formats, the SIWE message fields, TTL and nonce rules, the venice-x402-client SDK, and how to choose between the two modes.
SkillScore100Maintained
Automatic
◆AI Engineer pack
Last verified 8/20/2026
What it changes
Passed 22 of 22 test cases with the skill, and 12 of 22 without it.
Without skill55%
With skill100%
Checks it passed that the model alone missed
The response specifies chain ID 8453
The base64 encoded payload includes the address field
The response specifies the endpoint path /x402/top-up
and 15 more in the full report
10 fixed12 passed either way0 still failing0 broke
Pass-rate lift
+45 pp
Tokens
+70%
Agent turns
0%
Response time
-59%
Model gemini-3.6-flashMeasured 8/20/2026v122 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 10 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 10
Prompt
What specific error code string does Venice AI return if an application reuses a SIWE nonce within the active tracking window?
What was checked, without and with the skill
Checked
Without skill
With skill
The response identifies the code X402_SIGN_IN_NONCE_REUSED
Missed
Passed
case-10 · gemini-3.6-flash · 8/20/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md178 linessingle file
Venice Authentication
Every Venice endpoint accepts one of two auth schemes, declared in the OpenAPI spec as BearerAuth and siwx. Both are first-class — pick whichever fits the deployment.
Use when
You're making your first call to api.venice.ai.
You're building a server-side integration (usually Bearer) or an agent / no-account wallet flow (x402).
You hit 401 Authentication failed and need to check header format.
You're implementing SIWE signing manually instead of using the SDK.
Use the Bearer scheme when you have a Venice account, want usage analytics (/billing/usage-analytics), want to issue scoped child keys, or need DIEM / bundled credit priority.
Option B — x402 wallet (SIWE)
Authenticate with an Ethereum wallet. No account needed. Pay per request in USDC on Base (chain ID 8453). Balance lives under your wallet address and is consumed automatically.