# RelayStation PDF Watermark

> RelayStation PDF Watermark is a paid API for AI agents from api.relaystation.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-16).

Stamps a text watermark (e.g. DRAFT, CONFIDENTIAL, or custom text) across pages of a PDF document with configurable position, opacity, color, and size

## Facts

- Endpoint: POST https://api.relaystation.ai/v1/pdf/watermark
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/relaystation-pdf-watermark-c31dc093
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6cI3sqO08zaTYRc8bzp-1

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-pdf-watermark-c31dc093 -d '<json body>'
```

Example prompt: Take this PDF file and stamp 'CONFIDENTIAL' in red text at a 0.3 opacity diagonally centered on every page — I need to share it externally and want the watermark clearly visible but not blocking the content.

## When to prefer this

Choose this endpoint when you need to programmatically add visible text watermarks to PDF documents at low cost ($0.001/page), especially within an automated agent workflow that handles document distribution or review cycles. Ideal when you need fine-grained control over watermark position, opacity, color, and page range selection without standing up your own PDF processing infrastructure.

## Known failure modes

- File too large (>50 MB via inputKey or >4 MiB inline base64) returns an error
- Invalid color hex pattern causes schema validation failure
- Invalid page range string returns a parsing error
- Malformed or corrupt PDF input returns a processing error
- Opacity value outside 0–1 range fails schema validation
- Text exceeding 500 characters is rejected

## How this service works

$0.001/page. Stamp text watermarks across PDF pages — DRAFT, CONFIDENTIAL, or your own. 1¢ x402 min; remainder auto-credits — relaystation.ai/penny

## Output

Returns a watermarked PDF file with the specified text overlaid on the requested pages. The output PDF has the watermark applied at the configured position, color, opacity, and font size, with all original content preserved underneath.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {
      "file": {
       "type": "object",
       "description": "cputools input-source: { inline: <base64 ≤ 4 MiB> } or { inputKey: <scratch key from /v1/cputools/upload-url, ≤ 50 MB> }."
      },
      "size": {
       "type": "integer",
       "maximum": 400,
       "minimum": 1
      },
      "text": {
       "type": "string",
       "maxLength": 500,
       "minLength": 1
      },
      "color": {
       "type": "string",
       "pattern": "^#?[0-9a-fA-F]{6}$"
      },
      "pages": {
       "type": "string",
       "description": "1-based pages/ranges, \"all\" or \"1-3\" (default all)."
      },
      "opacity": {
       "type": "number",
       "maximum": 1,
       "minimum": 0
      },
      "position": {
       "enum": [
        "center",
        "top-left",
        "top-right",
        "bottom-left",
        "bottom-right"
       ],
       "type": "string"
      }
     }
    },
    "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-pdf-watermark-c31dc093/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)