Created on 10th June 2025
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One of society’s biggest problems is how do we know what’s true? As trust in traditional media steadily declines and AI-generated fake news spams the internet, prediction markets emerge as a new real-time news source powered by collective intelligence.
The TrueCast API aggregates real-time news, social media sentiment, and other data sources, then grounds them by prediction market odds (if available) to provide verified insights and fact checks.
Here is how it works:
Ways to access the x402 protected API:
const account = await cdp.evm.getOrCreateAccount({ name:
${authorFid}, });
1)The NextJs x402 example could not be ported to the base mainnet facilitator as a there is a 'crypto' dependency on cdp-sdk limiting @coinbase/x402's compatibility to nodejs runtimes. After contacting the CDP team, a temporary workaround was quickly proposed, https://github.com/coinbase/x402/pull/224.
2)On the chat UI, it is inconvenient to have repeated wallet popups for each prompt. Thus I wanted to use CBW subaccounts for an improved user experience. However the subaccount feature is still in beta and only supports base-sepolia and ETH spending limits, while the x402 facilitator only supports USDC payments. To mimic the intended experience as closely as possible I implemented to following strategy as temporary workaround:
3)The created CDP v2 user wallets only need to be funded with USDC to use x402pay, as gas is sponsored by the facilitator. However, if a user wants to withdraw the balance, gas is needed. I first tried using CDP v2 smart accounts + paymaster but signedTypedData needed for x402 is not supported. The solution I found is to only sign a transferWithAuthorization with the user wallet and then submit the transaction with an admin CDP v2 wallet sponsoring the gas.
Note:
The API with all features discussed above was developed to be used in an existing project. The API works standalone and has been developed entirely during the hackathon as can be verified from the git history, relevant code is in neynar-webhook and x402-next-standalone folders.
Tracks Applied (3)
Amazon Web Services
Pinata
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