Perplexity via x402: research supplier pricing with sources

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We investigated whether Perplexity's Sonar Pro could help an agent prepare a supplier-pricing brief. We checked the x402engine route and obtained a free quote for a specific prompt comparing Exa and Tavily. We've included the exact request, quoted cost and evidence checks so you can assess a trial without starting from a general product description.

We chose pricing research because a price alone isn't enough to compare suppliers: the charging unit and its conditions matter. The useful deliverable is a short answer with official source links that someone can verify. We priced that request; we haven't purchased or assessed the resulting answer.

Perplexity's Sonar Pro documentation establishes its search-and-citation capability. The gateway service record identifies OpenRouter as x402engine's upstream provider. The access path here therefore includes both intermediaries.

Buy a narrow research answer

The desired deliverable is a short evidence table: provider, official source URL, pricing unit and date checked. An answer that names two prices without showing their basis has failed the job, even if its prose is confident.

This request keeps the scope small enough to inspect:

{
  "messages": [
    {
      "role": "user",
      "content": "Find the official pricing pages for Exa and Tavily. Return each URL, the pricing unit, and the date checked. Cite sources and mark anything unverified."
    }
  ],
  "max_tokens": 500
}

Save it as request.json. The paid endpoint is POST https://x402engine.app/api/llm/perplexity. First obtain a free quote for that body:

curl https://x402engine.app/api/llm/perplexity/quote \
  -H 'Content-Type: application/json' \
  --data-binary @request.json

Our request on 7 September 2026 returned $0.036082 USD, with a 500-token output budget. This is an observed quote for the displayed request, not a flat price for every research question. The gateway schema identifies this route as Sonar Pro and prices model requests through quotes.

Turn the answer into evidence

The research target is concrete, but we have not purchased its answer. The following is an acceptance template, not returned data:

Field	What the reviewer needs
Provider	Exa or Tavily, with the relevant product named
Source	The official pricing URL, opened successfully
Unit	What a charge buys: request, credit, page or another stated unit
Conditions	Parameters or plan rules that change the comparison
Checked	When the source was inspected

Open the cited pages before reusing the result in a recommendation. Confirm that the text supports the specific price and unit. A citation to a provider homepage is insufficient if the claim concerns an endpoint's charging rules. If the model cannot establish a field, keep it unknown instead of filling it from memory.

The prompt's request for a date also needs checking. A generated “checked today” is not independent evidence that a page was retrieved today. Preserve the source URLs and your own inspection date with the finished brief.

When to use Sonar rather than raw search

This route is useful when you want a first research answer that already connects findings. Exa or Tavily may fit better when the workflow needs search records and source text as separate inputs it can process itself. These are different deliverables, so compare the work saved as well as the request price.

For a recurring supplier watch, store the previous verified table and request only the fields that need refreshing. Treat a reported change as a lead to inspect. Repeating a long, open-ended market-research prompt makes both its bill and its acceptance criteria harder to control.

Access and the next step

The operator of this route is x402engine, not Perplexity's direct API. Follow the gateway client documentation to configure payment, then submit the same body whose quote you accepted. Changes to the prompt or output budget warrant a new quote.

For a first trial, we'd use this two-provider brief to check the paid answer, citation forwarding and source quality before expanding to a market report.