Which sizes does the invite-card template support?

1200×630, 1080×1080. The default is 1200×630; pass width and height to pick another supported size.

Which parameters are required?

headline. Every other parameter is optional and has a rendering default.

Does rendering the same parameters twice cost twice?

No. The same template version, parameters, brand kit version, format, and size produce the same cache key, so a repeat request is served from cache instead of rendering again. Billing is not connected yet in early access.

Template · invite-card@1

Invite card template

The invite-card template renders an invitation or referral card with the inviter, a code on a ticket stub, and a call to action. Send JSON parameters through the remote MCP server, POST /v1/renders, or a signed /i/invite-card.png URL; the default size is 1200×630.

Sizes: 1200×630 · 1080×1080
Formats: PNG · JPEG · WebP
Version: 1.0.0

VectorFast Render is in early access. Billing is not connected yet, and API keys are issued to waitlist members as access opens. Join the waitlist

Preview

Rendered by VectorFast Render from this template's English and Chinese example parameters, through the same signed URLs your own pages would use.

Preview images are signed on the server and are not available in this environment.

Ask your agent

Paste the prompt into Claude, Cursor, or another agent connected to the VectorFast Render MCP server. The JSON is the render tool call it should turn into.

Prompt

Make a referral card Ana Lima can send to friends: "Ana invited you to VectorFast Render", code ANA-2026 good until November 30, and a "Claim 100 free renders" button.

MCP render call

{
  "name": "render",
  "arguments": {
    "template": "invite-card",
    "params": {
      "headline": "Ana invited you to VectorFast Render",
      "inviter_name": "Ana Lima",
      "code": "ANA-2026",
      "cta": "Claim 100 free renders",
      "expires": "Valid until Nov 30"
    }
  }
}

Connect Claude to VectorFast Render

Parameters

Read from the schema that POST /v1/renders validates. String values are trimmed; anything over a limit is rejected with invalid_params.

Invite card template parameters
Param	Type	Required	Limit	Notes
headline	string	Yes	≤ 90 chars	Invitation headline.
inviter_name	string	No	≤ 40 chars	Who sent the invite.
code	string	No	≤ 16 chars	Referral or access code on the ticket stub.
cta	string	No	≤ 30 chars	Button text.
expires	string	No	≤ 30 chars	Free text such as "Valid until Nov 30".

Render it from code

The REST call needs an API key in Authorization: Bearer. Its response includes a signed url you can store and reuse as an og:image. The Node.js function shows the signing algorithm the server verifies; per-key signing secrets are not issued yet in early access, and the secret must stay on your server.

curl · POST /v1/renders

curl https://vectorfast.ai/v1/renders \
  -H "Authorization: Bearer $VECTORFAST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "template": "invite-card@1",
  "format": "png",
  "width": 1200,
  "height": 630,
  "params": {
    "headline": "Ana invited you to VectorFast Render",
    "inviter_name": "Ana Lima",
    "code": "ANA-2026",
    "cta": "Claim 100 free renders",
    "expires": "Valid until Nov 30"
  }
}'

Node.js · signed URL (server-side only)

import { createHmac } from 'node:crypto'

// Server-side only. Never ship the signing secret to a browser, a mobile app or a repo.
const SIGNING_SECRET = process.env.VECTORFAST_SIGNING_SECRET

function encode(value) {
  return encodeURIComponent(value).replace(/[!'()*]/g, c => '%' + c.charCodeAt(0).toString(16).toUpperCase())
}

export function signRenderUrl({ template, format = 'png', params, brand, width, height, keyId }, secret = SIGNING_SECRET) {
  const query = {}
  for (const [key, value] of Object.entries(params)) {
    if (value === undefined || value === null)
      continue
    query[key] = typeof value === 'string' ? value : Array.isArray(value) ? JSON.stringify(value) : String(value)
  }
  if (brand) query.brand = brand
  if (keyId) query.k = keyId
  if (width) query.w = String(width)
  if (height) query.h = String(height)

  const canonical = Object.entries(query)
    .map(([key, value]) => [encode(key), encode(value)])
    .sort((a, b) => (a[0] < b[0] ? -1 : a[0] > b[0] ? 1 : a[1] < b[1] ? -1 : a[1] > b[1] ? 1 : 0))
    .map(([key, value]) => key + '=' + value)
    .join('&')
  const path = '/i/' + template + '.' + format
  const sig = createHmac('sha256', secret).update(path + '?' + canonical).digest('base64url')
  return 'https://vectorfast.ai' + path + '?' + (canonical ? canonical + '&' : '') + 'sig=' + sig
}

const url = signRenderUrl({
  template: 'invite-card',
  format: 'png',
  width: 1200,
  height: 630,
  params: {
    "headline": "Join the team on VectorFast Render",
    "inviter_name": "Mia Chen",
    "code": "TEAM-42",
    "cta": "Accept invite",
    "expires": "Expires Nov 30"
  },
})

How signed URLs work

Invite card template FAQ

Which sizes does the invite-card template support?: 1200×630, 1080×1080. The default is 1200×630; pass width and height to pick another supported size.
Which parameters are required?: headline. Every other parameter is optional and has a rendering default.
Does rendering the same parameters twice cost twice?: No. The same template version, parameters, brand kit version, format, and size produce the same cache key, so a repeat request is served from cache instead of rendering again. Billing is not connected yet in early access.

Updated 2026-10-30 · Markdown version