---
name: mpp-session-flow
description: >
  Implement MPP session-based streaming payment flows — authorize-once
  pay-as-you-go patterns for continuous data feeds, per-token billing, and
  micropayment aggregation. Use when building streaming APIs or services that
  charge incrementally.
---

# MPP Session Flow (Streaming Payments)

## Before writing code

**Fetch live docs**:
1. Fetch `https://www.npmjs.com/package/mppx` for the session middleware API and payment channel configuration
2. Fetch `https://paymentauth.org/` for the canonical session intent specification
3. Web-search `mpp session streaming micropayments payment channel` for session implementation patterns
4. Web-search `site:mpp.dev session` for session-specific documentation

## Conceptual Architecture

### What Session Intent Is

The session intent implements **streaming micropayments** — often described as **"OAuth for money"**. The agent authorizes a spending limit upfront, then streams micropayments continuously as it consumes resources:

```
1. Client opens session with spending cap
2. Server creates payment channel
3. Client makes requests — each deducts from the spending cap
4. Micropayments stream at sub-cent costs, sub-millisecond latency
5. Session closes — final settlement on-chain (single transaction)
```

### When to Use Session

- **Per-token billing** — LLM inference charged per token generated
- **Continuous data feeds** — Real-time market data, sensor streams
- **Compute metering** — Pay for actual CPU/GPU seconds used
- **Bandwidth metering** — Pay per KB transferred
- **Any high-frequency, low-value access pattern**

### Session vs Charge Comparison

| Dimension | Charge | Session |
|-----------|--------|---------|
| Settlement | Per-request on-chain/card | Aggregated at session close |
| Latency | Includes payment settlement per call | Sub-millisecond after session open |
| Cost | One tx per request | One tx for entire session |
| Pricing | Fixed per request | Variable, metered |
| Use case | Infrequent, high-value calls | Frequent, low-value calls |

### Server-Side Implementation

```typescript
// Protect a route with a session payment gate
app.get('/api/stream', mppx.session({ maxAmount: '10000' }), async (c) => {
  // Deducts from the session's spending cap
  return c.json({ data: 'streaming content' });
});
```

### Session Lifecycle

1. **Open** — Client sends initial request; server returns 402 with session challenge
2. **Authorize** — Client authorizes spending cap (e.g., 10,000 units)
3. **Active** — Client makes requests; each deducts from the cap
4. **Refill** — Client can extend the cap before it runs out
5. **Close** — Either party closes; final settlement happens on-chain
6. **Settled** — Single on-chain transaction for the total consumed amount

### Payment Channel

Session payments use a **payment channel** — an off-chain mechanism where:
- Funds are locked upfront in a channel
- Each micropayment updates the channel state without on-chain transactions
- Only the opening and closing transactions go on-chain
- This enables thousands of sub-cent payments at sub-millisecond latency

### Spending Cap Management

- Agent sets the maximum they're willing to spend in the session
- Server deducts from this cap per request/unit consumed
- Agent can monitor remaining balance
- If cap is exhausted, server returns 402 for a new session
- Agent can proactively extend the cap

### Metering Patterns

| Pattern | Description |
|---------|-------------|
| Fixed per request | Each request costs a fixed amount |
| Per-unit | Cost varies by units consumed (tokens, bytes, seconds) |
| Time-based | Cost accrues per time interval |
| Tiered | Rate decreases with volume (first 100 at $X, next 1000 at $Y) |

### Best Practices

- Set reasonable default spending caps (not too high for safety, not too low for UX)
- Implement cap exhaustion warnings before the cap runs out
- Log metering data for billing reconciliation
- Handle session interruptions gracefully (network drops, server restarts)
- Implement session resumption where possible
- Monitor session durations and spending patterns for pricing optimization

Fetch the latest mppx SDK documentation and MPP specification for exact session API, payment channel mechanics, and configuration options before implementing.


---
Source attribution: OrcaQubits
Original project: https://github.com/OrcaQubits/agentic-commerce-skills-plugins/blob/30cd25c74c8aa7dc49b3ec4847d463f6104439f6/dist/codex/stripe-mpp/skills/mpp-session-flow/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2024-2026 OrcaQubits AI (https://orcaqubits-ai.com)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: OrcaQubits
Original project: https://github.com/OrcaQubits/agentic-commerce-skills-plugins/blob/30cd25c74c8aa7dc49b3ec4847d463f6104439f6/dist/codex/stripe-mpp/skills/mpp-session-flow/SKILL.md
Attribution basis: Source repository record

Fields of work: Data & Analytics, Development & Engineering, Marketing, Sales
Roles: Backend Developer, Data Analyst, Growth Marketer, Product Marketer, Sales Engineer
Specialties: API, Backend
Tools: Mppx, Paymentauth
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 0653c1524a54b603dc097b81b9c05914141accad3896a5ef17c36f3d2f312c25