> ## Documentation Index
> Fetch the complete documentation index at: https://sella.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Register a pay-per-call API in the Sella Data Market

> Register your API in the Sella Data Market. Agents discover, dry-run, and pay per call through a Sella wallet — your upstream keys stay yours.

The Sella Data Market lets you register any HTTP API as a pay-per-call product. Agents discover your endpoint through the marketplace, route calls through Sella's wallet proxy, and settle in USDC — you never hand over credentials, and you earn on every request. Registration normalizes your API into the same index agents search every time they need a capability.

## How agents reach your API

Agents don't call you directly. Sella normalizes your endpoint into its registry, agents discover it with `list_market_apis`, and calls are routed through the AgentWallet proxy — which handles [x402](/reference/x402) or MPP settlement and forwards the verified request to your upstream service.

<CardGroup cols={2}>
  <Card title="No key handoff" icon="key-round" href="/reference/x402">
    Agents authenticate to Sella, not to you. Your upstream credentials stay entirely yours — buyers never see them.
  </Card>

  <Card title="Paid per call" icon="coins" href="/publishers/pricing">
    Every routed request settles in USDC to your wallet at the price you set. No invoicing, no reconciliation.
  </Card>
</CardGroup>

## Register your API

Open **[Dashboard → Listings → New → API](https://sellag.vercel.app/dashboard/listings/new)** and fill in the fields below. The quality of your schema and description directly determines the quality of the agent skill Sella generates for your endpoint.

<ParamField path="endpoint" type="string" required>
  The base URL and route(s) agents will call. Must be a publicly reachable HTTPS address.
</ParamField>

<ParamField path="schema" type="OpenAPI / JSON Schema">
  Input and output definitions for your endpoint. A precise schema lets Sella generate accurate agent instructions and allows agents to pre-validate inputs before sending a paid request.
</ParamField>

<ParamField path="pricing" type="object" required>
  `fixed` — a set USDC amount charged per call. `dynamic` — a min–max range resolved at runtime by the 402/MPP payment challenge.
</ParamField>

<ParamField path="protocols" type="string[]">
  The payment standards your endpoint accepts: `x402`, `MPP`, and/or `SIWX` (identity-gated, free tier).
</ParamField>

<ParamField path="chains" type="string[]">
  Settlement chains you accept for payment, for example `base` or `solana`.
</ParamField>

## Generated skills

Sella turns your registration into a machine-readable **skill** — a generated instruction file served at `GET /api/endpoints/{id}/skill.md`. The skill tells agents when to use your endpoint, what inputs it expects, what it returns, what it costs, and which payment protocols and networks it supports. Better schemas and richer descriptions produce more useful skills, which drive more calls to your endpoint.

## The trust layer

Every provider in the Data Market carries trust signals that agents can filter on. Build these up over time to become the preferred choice when multiple providers offer similar capabilities.

<CardGroup cols={3}>
  <Card title="verified" icon="badge-check" href="/publishers/quality">
    Sella-verified providers can be surfaced exclusively through the `verified_only` filter, making verification a meaningful competitive advantage.
  </Card>

  <Card title="qualityScore" icon="star" href="/publishers/quality">
    A quality signal derived from Sella's ongoing evaluation of your endpoint's responses and schema accuracy.
  </Card>

  <Card title="reliability" icon="activity" href="/publishers/quality">
    Uptime and response consistency measured over time. Agents running critical workflows weight this heavily.
  </Card>
</CardGroup>

<Info>
  Sella also ingests providers automatically from public registries through its catalog pipeline — connectors, normalize, classify, and dedupe — re-synced daily. Self-registering puts you in the same normalized index those automated entries land in, with the benefit of your own controlled metadata.
</Info>

## Getting paid

Settlement happens per call, in USDC, to your wallet, minus the 3% platform fee. You don't need to do anything between a call completing and your earnings landing. Track your balance and withdraw from the [Dashboard → Earnings](https://sellag.vercel.app/dashboard/earnings) page — see [Pricing & earnings](/publishers/pricing) for the full payout flow.

<Card title="See it from the buyer side" icon="eye" href="/consumers/api-market" horizontal>
  How agents discover, dry-run, and pay for API calls in the Data Market.
</Card>