[Intermediate/Advanced] Fix Pollar's own Nirium x402 demo tab (real PR to pollar-xyz/demo)

[Eras256]

Difficulty: Intermediate/Advanced (6/10). ~10–16h. TypeScript/Next.js, familiarity with nirium-pollar-adapter and x402.

Context

Pollar (Stellar-native onboarding/wallet SDK) already ships a "Nirium x402" tab in their own public demo — pollar-xyz/demo, live at demo.pollar.xyz/adapters/nirium — but it's a stub written before nirium-pollar-adapter existed:

• app/adapters/nirium/x402/adapter.ts builds a classic Stellar Operation.payment() and calls it x402. That's not x402 — no 402 challenge, no auth-entry signing, no facilitator settlement.
• app/adapters/nirium/adapter/page.tsx documents an aspirational agent.x402.buildPayment(p) method that does not exist in the published nirium package. The real client-side primitive is x402Fetch().

This issue is an external contribution to Pollar's own repo, not another example in this repo — it only counts if a real PR lands against pollar-xyz/demo. Reference implementation to follow already exists and is merged: pollar-xyz/pollar-apps#30 (apps/adapters/nirium) uses the exact real pattern — usePollar().getClient() → createPollarSigner() → createNiriumAdapter({ signer, network }).x402Fetch(url) — verified end-to-end with a real settled testnet payment.

Goal

Replace the stub in pollar-xyz/demo's Nirium tab with the real nirium-pollar-adapter integration, so demo.pollar.xyz/adapters/nirium actually performs a live x402 payment instead of a mislabeled classic payment.

Scope / Deliverables

1. Add nirium-pollar-adapter as a dependency (@pollar/core/@pollar/react are already ^0.11.1 there — compatible).
2. Rewrite app/adapters/nirium/x402/adapter.ts's pay function to use createPollarSigner(pollarClient) + createNiriumAdapter({ signer, network }).x402Fetch(url) against a real Nirium endpoint (GET /api/v1/premium/market, $0.05 USDC, testnet — see pollar-apps#30's apps/adapters/nirium/lib/nirium.ts for the exact working call).
3. Update app/adapters/nirium/adapter/page.tsx's documented source snippet to match the real API (x402Fetch, not the invented buildPayment).
4. Show the actual response and settlement tx hash (linked to Stellar Expert) in the UI — same pattern as pollar-apps#30's result panel.
5. PR against pollar-xyz/demo explaining the before/after — this fixes a real, published-and-live inaccuracy about how Nirium's protocol works, not just an enhancement.

Acceptance criteria

• A real PR opened against pollar-xyz/demo — link it here. Merge isn't required, but it must be a genuine working replacement, not a doc-only edit.
• Demonstrated end-to-end on testnet: a real settled tx, hash included and independently verified on Horizon before claiming it works (same standard as this repo's other external-integration issues).
• Testnet only. Never touches Pollar's own SDK internals — only this one demo page.

Out of scope

• Modifying @pollar/core/@pollar/react themselves.
• Any Pollar route besides app/adapters/nirium/.
• Mainnet.

Pointers

• Reference implementation (already merged, ours): pollar-xyz/pollar-apps#30, specifically apps/adapters/nirium/lib/nirium.ts and hooks/useNiriumPayment.ts.
• nirium-pollar-adapter (npm): https://www.npmjs.com/package/nirium-pollar-adapter — source: https://github.com/nirium-protocol/nirium-pollar-adapter
• The stub to replace: https://github.com/pollar-xyz/demo/blob/main/app/adapters/nirium/x402/adapter.ts
• Dev docs: https://nirium.xyz/developers
• Questions: comment directly on this issue.

Reward

Eligibility is subject to GrantFox review under this campaign. Rewards are decided by GrantFox based on quality and available budget and are not guaranteed.

[ReinaMaze]

GM Maintainer, Can I get assigned to work on this?
I’ll replace the x402 stub with the real Nirium integration, update the UI/docs, and verify a successful testnet payment with the settlement transaction hash.
I’ll also open the required PR against pollar-xyz/demo.

ETA: 15 hours

[dair7]

I'd like to take this one.

Plan, following the reference in pollar-xyz/pollar-apps#30:

1. Add nirium-pollar-adapter to pollar-xyz/demo (@pollar/core / @pollar/react are already on ^0.11.1, so no version bump needed).
2. Rewrite pay in app/adapters/nirium/x402/adapter.ts to drop the Operation.payment() path and use the real flow: usePollar().getClient() → createPollarSigner(client) → createNiriumAdapter({ signer, network }).x402Fetch(url), pointed at GET /api/v1/premium/market ($0.05 USDC, testnet).
3. Fix the documented snippet in app/adapters/nirium/adapter/page.tsx — it advertises agent.x402.buildPayment(p), which doesn't exist in the published package; it should show x402Fetch.
4. Add the result panel showing the response body plus the settlement tx hash linked to Stellar Expert, same shape as the result panel in pollar-apps#30.

Testnet only, scoped to app/adapters/nirium/, no changes to Pollar SDK internals. I'll verify the settled tx on Horizon before claiming it works and link the PR here once it's open.

One question: is there a preferred contact on the Pollar side to give a heads-up before opening the PR, or should I just open it cold against main?

[angelraph]

Hi Eras256, I’d like to take on #85.

I went through the issue and the existing reference implementation in "pollar-xyz/pollar-apps#30", and I understand the main problem. The current demo is presenting a classic Stellar payment as x402, while the published Nirium integration now has a proper 402 → signing → settlement flow.

My plan is to:

• Add "nirium-pollar-adapter" to "pollar-xyz/demo" without changing the existing Pollar SDK versions.
• Replace the "Operation.payment()" implementation in "app/adapters/nirium/x402/adapter.ts" with the real flow using "usePollar().getClient()", "createPollarSigner()", "createNiriumAdapter()", and "x402Fetch()".
• Target the documented testnet "/api/v1/premium/market" endpoint and follow the working pattern from "pollar-apps#30".
• Update the demo documentation so it reflects the actual published Nirium API instead of the unavailable "buildPayment()" method.
• Add the payment result and settlement transaction hash to the UI, with the transaction independently verified on Horizon.
• Test the complete flow on testnet and open the required PR directly against "pollar-xyz/demo".

I’ll keep the changes limited to the Nirium demo integration and won’t touch Pollar SDK internals.

I can take responsibility for the full implementation, testing, and external PR rather than treating this as a documentation-only fix.

[GazzyLee]

I’d like to take this on. I’ll replace the stub with the real nirium-pollar-adapter x402 flow, following the existing pollar-apps#30 implementation as the reference.

I’ll update the adapter and docs, display the response and settled transaction hash in the demo, then verify the flow end-to-end on Testnet and open a working PR against pollar-xyz/demo.
please assign