# Relaystation Media Metadata Reader/Writer

> Relaystation Media Metadata Reader/Writer is a paid API for AI agents from api.relaystation.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Read or write media container tags (e.g. ID3, EXIF, MP4 atoms) as JSON without re-encoding the file via stream-copy

## Facts

- Endpoint: POST https://api.relaystation.ai/v1/media/metadata
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/relaystation-media-metadata-reader-writer-ef655e4e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_43SBkb7HmAMRkzAXxuB82

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 relaystation-media-metadata-reader-writer-ef655e4e -d '<json body>'
```

Example prompt: Can you read all the container tags from this MP3 file at https://example.com/track.mp3 and give them back to me as JSON — things like title, artist, album, year?

## When to prefer this

Choose this endpoint when you need to read or write media container tags (ID3, MP4 atoms, EXIF, etc.) without transcoding or re-encoding the file. It is specifically designed for stream-copy tag operations on audio and video files, making it faster and lossless compared to FFmpeg-based re-encode workflows. Prefer it over general-purpose media pipelines when the only goal is metadata inspection or tag updating.

## Known failure modes

- Unsupported container format — returns error if file type has no recognized tag structure
- Inaccessible file URL — returns error if the media file cannot be fetched
- Malformed JSON payload on write — returns validation error if tag fields are invalid
- File too large or timeout — slow remote files may cause request timeout
- Insufficient x402 credit balance — payment not fulfilled causes rejection

## How this service works

$0.0002/call. Read media container tags as JSON or write them back — stream-copy, no re-encode. 1¢ x402 min; remainder auto-credits — relaystation.ai/penny

## Output

Returns a JSON object containing all container tag key-value pairs read from the media file (e.g. title, artist, album, year, genre, comment, codec info), or a confirmation response after writing tags back to the file via stream-copy with no re-encoding.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {
      "set": {
       "type": "object",
       "additionalProperties": {
        "type": [
         "string",
         "number"
        ]
       }
      },
      "file": {
       "type": "object",
       "description": "cputools input-source: { inline: <base64 ≤ 4 MiB> } or { inputKey: <scratch key ≤ 50 MB> }. The input container must sniff (ffprobe) to the live allowlist (operator-tunable cputools.media.input_formats): 3g2, 3gp, aac, asf, avi, flac, flv, gif, m4a, m4v, matroska, mj2, mov, mov,mp4,m4a,3gp,3g2,mj2, mp3, mp4, mpeg, mpegts, mpegvideo, ogg, wav, webm, wmv. An off-list input is a free 422 UNSUPPORTED_FORMAT."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "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/relaystation-media-metadata-reader-writer-ef655e4e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.relaystation.ai](https://www.zero.xyz/host/api.relaystation.ai/llms.txt)