Core Concepts — Overview

Sylan is a decentralized API marketplace that coordinates on‑chain escrow & consensus with off‑chain nodes to deliver reliable API responses. This page orients you to the moving parts before you dive deeper.

Sylan is in active development. Only trust addresses listed under Architecture → Addresses & ABIs and announcements on official channels.

The mental model

Providers list APIs and define plans: PayPerCall (PPC) or Subscription.
Consumers pay in SYL; each request becomes an escrow‑backed task.
Nodes fetch from Providers, reach consensus off‑chain, and submit a result.
Escrow settles funds according to the outcome; fees split by BPS (basis points) across Provider / Nodes / Platform, totaling 10,000.

Actors & responsibilities

Actor	What they do	Key interactions
Provider	Publishes API listing, sets pricing & plan rules, maintains uptime & docs.	Registers listing in AccessRegistry; receives fees on successful calls.
Consumer	Selects a plan and initiates requests.	Approves SYL to APIEscrow; locks funds per call or maintains a subscription balance.
Node	Retrieves data from Provider endpoints and participates in consensus.	Registered in NodeRegistry; can be rewarded or slashed based on performance.
Protocol	Smart contracts enforcing payment, settlement, and integrity.	APIEscrow, APIConsensus, AccessRegistry, EventLogger, SylanToken, SylanStaking.

Deep dives live in Contracts and Architecture sections—this page stays conceptual.

Core primitives

apiId (bytes32): stable identifier for an API listing.
Descriptor: uri, contentHash, updatedAt, version—points to off‑chain metadata the client/Node reads before calling.
Plan types: PayPerCall (PPC) or Subscription (time‑window or call‑allotment). See Plans & Pricing.
requestHash (bytes32): a compact hash of the request payload (path, params, headers, etc.) used to bind funding → specific work.
expiresAtMs (uint64): millisecond unix timestamp; guards against replay/late settlement.
BPS split: {providerBps, nodeBps, platformBps} must sum to 10,000.

Economics at a glance

Consumer approves and locks SYL for a request (or tops up a subscription).
Nodes execute, the protocol finalizes via consensus, and APIEscrow settles:
- Success → split: Provider + Participating Nodes + Platform fee.
- Failure/Timeout → refund per plan rules; potential slashing for faulty Nodes.
Optional: Providers/Nodes can participate in staking for rewards & reputation.

End‑to‑end flow (conceptual)

This diagram is illustrative. Exact event names, method signatures, and proofs are documented under Architecture → Events and Contracts.

What’s not on this page

Implementation specifics (ABIs, addresses) → see Architecture → Addresses & ABIs.
Code samples → see Quickstart, Integrations, and contract pages.
Operational guides for Nodes/Providers → see Node and Provider sections.