Something strange is happening in the agent economy. The payment rails are built. USDC settlement works. The x402 protocol is processing billions in volume. Cloudflare, OSL, Coinbase, and Stripe have all shipped agent payment infrastructure in the last 30 days.
But agents still can't reliably find something to buy.
The discovery layer — the storefront where agents browse, evaluate, and select paid APIs — is fragmenting into three competing models. Each has a different theory of what agents need. Each has different assumptions about trust, quality, and scale. Only one approach will define how the agent economy works at scale.
Here's the map.
How it works: One API key unlocks everything. Developers sign up once, get a single key, and can call 1,000+ APIs, 100+ AI models, data feeds, and SaaS tools. The aggregator handles billing — usage-based, per-call, fiat or crypto. The developer never has a direct relationship with any API provider.
The theory: Developers don't want to manage 50 API keys, 50 billing relationships, and 50 different payment methods. The aggregator absorbs all that complexity. It's the Stripe + AWS Marketplace model applied to agent APIs.
What it gets right:
Where it breaks:
How it works: A central authority pre-screens and lists endpoints. Quality standards are enforced. The discovery API is public (no auth required), but payments flow through Circle's infrastructure — Agent Wallets, Nanopayments, USDC settlement. Think "App Store for AI agents."
The theory: Agents need trusted endpoints, not just any endpoint. Curation solves the quality problem at the gate. Only endpoints that meet standards get listed. Agents can spend with confidence because the marketplace vouches for every listing.
What it gets right:
Where it breaks:
How it works: Anyone can register an endpoint. The marketplace verifies it programmatically — probe on registration, periodic health checks, automatic deactivation of dead services. Agents discover through a machine-readable catalog, try endpoints for free, and pay through whatever x402 facilitator they prefer. The marketplace doesn't sit in the payment path.
The theory: Agents need verified endpoints, not curated ones. Verification is algorithmic and scalable — probe, measure, deactivate if dead. Curation is human and bottlenecked. An open marketplace maximizes choice while automated verification provides the trust layer. The marketplace is discovery + verification, not discovery + payment processing.
What it gets right:
Where it breaks:
| Aggregator | Curated | Open | |
|---|---|---|---|
| Access model | One key → all APIs | Pre-screened catalog | Verified, self-serve registration |
| Trust mechanism | Aggregator reputation | Human curation | Automated probe verification |
| Payment model | Aggregator bills you | Integrated (Circle stack) | Bring your own facilitator |
| API provider freedom | Must onboard to aggregator | Must pass curation | Self-register, auto-verified |
| Agent lock-in | High | Medium | Low |
| Catalog scalability | Medium (onboarding bottleneck) | Low (human bottleneck) | High (automated) |
| Trial access | Free credits on signup | Varies | 15 free calls per endpoint, no signup |
| Best for | Developers who want one integration | Enterprises who need guaranteed quality | Agents who need maximum choice + verification |
The honest answer: it depends on what agents actually need at scale, and we don't know yet.
If agent developers value convenience above all — one key, one bill, zero thinking — the aggregator wins. AIsa's 150x growth suggests this is a real segment.
If enterprises drive agent adoption and require compliance-grade vendor management, the curated marketplace wins. Circle's institutional credibility is hard to replicate.
If the agent economy follows the internet's architecture — open protocols, decentralized discovery, competition at every layer — the open marketplace wins. HTTP didn't need a curator. Email didn't need an aggregator. The web's killer feature was that anyone could publish and anyone could access.
But there's a fourth possibility: all three coexist, serving different segments. Aggregators for convenience-seeking developers. Curated marketplaces for regulated enterprises. Open marketplaces for the long tail and the protocol-native crowd.
The real question isn't which model wins. It's which model generates the most transactions. And on that metric, the open marketplace has one structural advantage: it's the only model where the marketplace doesn't sit in the payment path. That means every transaction on an open marketplace is a direct agent-to-agent payment — the purest form of the agent economy.
We've spent two years building payment rails. That phase is ending. The next phase is about discovery — and discovery is where market structure gets decided.
Aggregators centralize access. Curators gatekeep quality. Open marketplaces automate verification.
Pick your model. But pick quickly. The agents are arriving on August 14, and they're going to need somewhere to shop.
minia2a is an open marketplace with 306 verified x402 endpoints. 15 free trials per service. No API key. No wallet required to start. Facilitator-agnostic. https://minia2a.uk