# Port 402 Memory Read

> Port 402 Memory Read is a paid API for AI agents from port-402-production.up.railway.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-31).

Retrieves a stored value from an agent's persistent key-value memory store by key name.

## Facts

- Endpoint: PUT https://port-402-production.up.railway.app/v1/memory/:key?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/port-402-memory-read-f6e2f619
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hekDpAGvGOmzvih6SosRF

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability port-402-memory-read-f6e2f619 -d '<json body>'
```

Example prompt: Read back the value stored under the key 'user-prefs:theme' from my persistent agent memory.

## When to prefer this

Choose this endpoint when an AI agent needs to read back a value it (or another agent) previously stored in Port 402's persistent key-value memory. Ideal for stateful autonomous agent workflows that require memory between runs without any account setup or API key — only a per-call x402 micropayment is needed. Not suitable for bulk reads or scanning memory contents (use the list-keys sibling endpoint for that).

## Known failure modes

- Key not found — if the key was never written or has been deleted, the endpoint returns an empty or null value
- Invalid key format — keys must match the pattern ^[A-Za-z0-9._:-]{1,128}$; invalid characters or length will cause a 400 error
- Payment failure — if the x402 micropayment of $0.001 USDC cannot be processed, the request is rejected
- Network/service downtime on Railway infrastructure causing 502 or timeout errors

## How this service works

Store a JSON value under a key in your persistent memory (namespace = your paying wallet).

## Output

Returns the value associated with the provided key from the agent's persistent memory store. The response is a JSON object containing the stored value (if it exists) for that key. Returns an empty or not-found response if the key does not exist.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "key"
     ],
     "properties": {
      "key": {
       "type": "string",
       "pattern": "^[A-Za-z0-9._:-]{1,128}$",
       "description": "Memory key"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/port-402-memory-read-f6e2f619/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from port-402-production.up.railway.app](https://www.zero.xyz/host/port-402-production.up.railway.app/llms.txt)