# Tenjin: Medium vs Substack Canonical URL Handling on Content Import

> Tenjin: Medium vs Substack Canonical URL Handling on Content Import is a paid API for AI agents from tenjin.blog, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Returns an article explaining how Medium and Substack each handle canonical URLs when importing or cross-posting content, with SEO-correct guidance and documented workarounds.

## Facts

- Endpoint: GET https://tenjin.blog/api/read/athoughts/medium-vs-substack-how-each-handles-canonical-urls-on-content-import
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tenjin-medium-vs-substack-canonical-url-handling-on-content-import-76dadf21
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dMrnT1--XNch9HK7lHHID

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 tenjin-medium-vs-substack-canonical-url-handling-on-content-import-76dadf21
```

Example prompt: Pull up the Tenjin article on how Medium and Substack handle canonical URLs when you import or cross-post content — I need to know the SEO-correct approach and any workarounds as of July 2026.

## When to prefer this

Use this endpoint when an agent or user needs authoritative, current guidance on canonical URL behavior specific to Medium and Substack content import — particularly when building cross-posting tools, auditing SEO strategy, or advising on duplicate content risk across these two platforms. Prefer this over generic SEO articles when the user specifically mentions Medium import, Substack cross-posting, or rel=canonical in a publishing context.

## Known failure modes

- Article not found if slug or handle is incorrect (404)
- Payment not processed or insufficient USDC balance (402 payment required)
- Creator handle does not match slug ownership
- Network timeout on retrieval

## How this service works

For anyone building a content-import/republish feature or advising a cross-poster: Medium's Import tool auto-sets rel=canonical to the source and backdates the post; Substack supports no canonical URL at all, so every post self-canonicals. The SEO-correct reference implementation and the documented cross-post workaround. As-of 2026-07-13.

## Output

The full text of a Tenjin article detailing how Medium's import tool sets rel=canonical to the source URL and backdates the post, how Substack lacks canonical URL support causing posts to self-canonical, and the SEO-correct reference implementation plus documented cross-post workarounds, as of 2026-07-13.

## 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": [
      "handle",
      "slug"
     ],
     "properties": {
      "slug": {
       "type": "string",
       "description": "The article's URL slug, unique per creator. The reserved slug `latest` resolves to the creator's newest published piece; its stable scheduled-read form is the wallet-address URL /api/read/<0x-address>/latest (a handle `latest` is not payable)."
      },
      "handle": {
       "type": "string",
       "description": "The creator's handle, or their wallet address. The address form is REQUIRED for a durable `latest` alias (a handle `latest` is not payable), and is the only form for an unclaimed creator."
      }
     }
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {},
     "additionalProperties": false
    }
   },
   "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/tenjin-medium-vs-substack-canonical-url-handling-on-content-import-76dadf21/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from tenjin.blog](https://www.zero.xyz/host/tenjin.blog/llms.txt)