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Overview

Payo uses two types of credentials:
CredentialUsed ByPurpose
Provider API KeyMCP ProvidersAuthenticate charge requests
Agent TokenAI AgentsIdentify who’s being charged
Both are secret keys that should never be shared publicly.

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Provider API Keys

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What They Are

Provider keys authenticate your MCP server to the Payo platform. When your server charges an agent, the provider key proves it’s really you.

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Format

sk_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx...
  • sk_ - Secret key prefix
  • live_ - Production environment
  • 64 hex characters - Unique identifier

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Scope

Provider keys have provider:charge scope, which allows:
  • Charging agents via /api/v1/charge
  • No other actions (can’t manage agents, can’t access admin features)

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Usage

Pass as environment variable to your MCP server: 
PAYO_API_KEY=sk_live_xxx node server.js
Used in SDK configuration: 
withPayments(server, {
  apiKey: process.env.PAYO_API_KEY!,
  pricing: { ... }
});

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Security

Your provider key is a secret. Exposure allows anyone to charge agents on your behalf.
Best practices:
  • Store in environment variables, never in code
  • Use secrets management (Vercel, Railway, AWS Secrets Manager)
  • Rotate periodically
  • Different keys for development vs production

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Agent Tokens

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What They Are

Agent tokens identify which agent is making a tool call. When an agent calls a paid tool, their token is used to charge their account.

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Format

Same as provider keys: 
sk_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx...

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Scope

Agent tokens have agent:connect scope, which allows:
  • Being charged for tool calls
  • No other actions (can’t charge others, can’t access platform features)

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Usage

stdio transport (Claude Desktop, Cursor): 
{
  "mcpServers": {
    "my-server": {
      "command": "node",
      "args": ["server.js"],
      "env": {
        "AGENT_TOKEN": "sk_live_agent_xxx"
      }
    }
  }
}
HTTP transport (custom agents): 
const response = await fetch(url, {
  headers: {
    'Authorization': 'Bearer sk_live_agent_xxx'
  }
});

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Security

Agent tokens control spending. Exposure allows anyone to spend your credits. Best practices:
  • Store securely (not in version control)
  • Use different tokens for different agents/environments
  • Monitor for unexpected charges
  • Rotate if compromised

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Key Storage

Keys are stored securely: 
Raw Key:        sk_live_abc123xyz789...
                    ↓
SHA256 Hash:    5d41402abc4b2a76b9719d911017c592...
                    ↓
Stored in DB:   key_hash = "5d41402abc..."
                key_prefix = "sk_live_"
                key_last4 = "9..."
The raw key is:
  • Shown once at creation
  • Never stored
  • Cannot be retrieved
Only the hash is stored for validation.

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Key Validation

When a key is used: 
1. Receive: sk_live_abc123xyz789...

2. Compute: SHA256("sk_live_abc123xyz789...") = "5d41402..."

3. Query:   SELECT * FROM api_keys
            WHERE key_hash = "5d41402..."
            AND deleted_at IS NULL

4. Check:   scopes @> '{required_scope}'

5. Return:  { workspace_id, key_name } or error
This allows validation without ever storing the raw key.

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Scopes

Each key type has a specific scope:
Key TypeScopePermissions
Providerprovider:chargeCall /api/v1/charge
Agentagent:connectBe charged for tool calls
Keys cannot perform actions outside their scope:
  • An agent token cannot charge other agents
  • A provider key cannot be charged

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Key Lifecycle

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Creation

  1. User clicks “Create Key” in dashboard
  2. System generates 64 random hex bytes
  3. Key is hashed and stored
  4. Raw key is displayed once

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Usage

  1. Key is passed to API or MCP server
  2. System hashes and looks up
  3. Validates scope and status
  4. Authorizes the action

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Rotation

  1. Create a new key
  2. Update your configuration
  3. Delete the old key

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Deletion

  1. User clicks “Delete” in dashboard
  2. Key is soft-deleted (deleted_at set)
  3. Key immediately stops working
  4. Key cannot be recovered

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Multiple Keys

You can create multiple keys for different purposes: Agents:
  • Separate keys per agent instance
  • Separate keys per environment
  • Easy to revoke one without affecting others
Providers:
  • Separate keys per MCP server
  • Separate keys per environment
  • Independent rotation schedules

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Common Issues

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”Invalid provider key”

  • Key was deleted
  • Key doesn’t exist
  • Key is from wrong account
  • Key was typed incorrectly
Fix: Create a new key in dashboard.

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”Invalid agent token”

  • Token was deleted
  • Token doesn’t exist
  • Token was typed incorrectly
Fix: Agent must create new token.

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”Token missing”

  • AGENT_TOKEN env var not set
  • Authorization header not sent
  • Configuration syntax error
Fix: Check agent configuration.