# fastapi.online — Image Watermark

> fastapi.online — Image Watermark is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0015/call, status down (last checked 2026-09-15).

Adds a text watermark to an uploaded image with configurable opacity and position

## Facts

- Endpoint: POST https://api.fastapi.online/image-watermark
- Price: $0.0015/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fastapi-online-image-watermark-bb95ed93
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_s6IKazg_oiEgPNGZ3SzYk

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 fastapi-online-image-watermark-bb95ed93 -d '<json body>'
```

Example prompt: Can you add a watermark to this product photo with the text '© Acme Corp 2024', placed in the bottom-right corner at 50% opacity?

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call watermarking operation without setting up your own image processing pipeline — especially useful for one-off or low-volume watermarking tasks where signup friction of larger SaaS tools is undesirable. Suitable for PNG, JPEG, and WebP images with simple text watermarks.

## Known failure modes

- Unsupported file format (non-PNG/JPEG/WebP) returns an error
- Missing required 'file' field returns a 422 validation error
- Invalid opacity value (out of expected range) may produce unexpected visual output
- Payment not included or insufficient results in 402 Payment Required
- Very large image files may time out or be rejected

## How this service works

Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&amp;A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding &amp; crypto utilities, date/time calculators, geo/coordinate math, math &amp; finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.

## Output

Returns a watermarked version of the uploaded image (PNG/JPEG/WebP) with the specified text overlaid at the chosen opacity and position

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "file": {
   "type": "string",
   "format": "binary",
   "description": "Image file (PNG/JPEG/WebP)"
  },
  "text": {
   "type": "string"
  },
  "opacity": {
   "type": "string"
  },
  "position": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fastapi-online-image-watermark-bb95ed93/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.fastapi.online](https://www.zero.xyz/host/api.fastapi.online/llms.txt)