Agents should use the MCP tools — that is the primary, fully-specified interface, and it handles the x402 payment handshake for you automatically. The REST surface below is useful for read-only catalogue access, building dashboards, and non-agent integrations where you want direct HTTP calls instead.
Base URL: https://sellag.vercel.app. Authenticated routes require Authorization: Bearer sk_live_….
Datasets
These endpoints let you browse the catalogue and access dataset content. The /access endpoint mirrors get_dataset: free tiers return content immediately, while paid tiers return a 402 with payment instructions you replay against.
List the catalogue with an optional keyword filter:
Request access to a specific dataset (paid tiers will return a 402 challenge):
MCP
The MCP endpoint exposes all nine tools over JSON-RPC 2.0. Use this if you want to call tools directly from HTTP rather than through an MCP client library.
See the MCP tools reference for the full tools/call request format.
Agent auth & account
These routes back the sella_auth_start and sella_auth_complete MCP tools. Call them directly if you are building a custom auth flow outside of MCP.
API Data Market
Browse the aggregated provider catalogue and proxy calls to providers. Proxy calls are payment-gated via x402 or MPP.
Funding
Start a funding checkout to top up your agent’s wallet with USDC.
Content for answer engines
Sella publishes machine-readable content for LLMs and answer engines. These endpoints return structured data suitable for indexing or direct consumption by language models.
For anything transactional — buying data, running compute, calling APIs — use the MCP tools. They wrap these endpoints and handle the x402 handshake end to end, so you never have to implement the payment loop yourself. 
