Payload CMS on AWS ECS Fargate

Lexical is Meta's open-source rich text editor framework — used by Facebook, WhatsApp, and since Payload CMS 3.x, as the default editor for all richText fields. It replaced Slate.js from Payload 2.x.

Lexical stores content as a JSON tree, not HTML. When you retrieve a richText field from the Payload REST API, you get a nested node structure. To render it on your Astro frontend, you need to walk that tree and convert each node to HTML. This part gives you the complete, production-ready implementation.

What the Lexical JSON Looks Like

{
  "root": {
    "type": "root",
    "children": [
      {
        "type": "heading",
        "tag": "h2",
        "children": [
          { "type": "text", "text": "About Our Department", "format": 0 }
        ]
      },
      {
        "type": "paragraph",
        "children": [
          { "type": "text", "text": "The ", "format": 0 },
          { "type": "text", "text": "Sheriff's Office", "format": 1 },
          { "type": "text", "text": " serves all residents.", "format": 0 }
        ]
      }
    ]
  }
}

The Text Format Bitmask

Text nodes use a bitmask integer to encode formatting. format: 3 means bold (1) AND italic (2) — check each bit with format & mask.

Step 1: The Lexical Renderer

Create src/lib/lexical.ts in your Astro project:

/**
 * Lexical JSON to HTML renderer
 * Compatible with @payloadcms/richtext-lexical 3.x
 */

export function lexicalToHtml(content: any): string {
  if (!content?.root?.children) return ''
  return renderNodes(content.root.children)
}

function renderNodes(nodes: any[]): string {
  if (!Array.isArray(nodes)) return ''
  return nodes.map(renderNode).join('')
}

function renderNode(node: any): string {
  if (!node) return ''

  if (node.type === 'text') {
    let text = escapeHtml(node.text || '')
    const fmt = node.format || 0
    if (fmt & 1)  text = `<strong>${text}</strong>`
    if (fmt & 2)  text = `<em>${text}</em>`
    if (fmt & 4)  text = `<s>${text}</s>`
    if (fmt & 8)  text = `<u>${text}</u>`
    if (fmt & 16) text = `<code>${text}</code>`
    if (fmt & 32) text = `<sub>${text}</sub>`
    if (fmt & 64) text = `<sup>${text}</sup>`
    return text
  }

  const children = node.children ? renderNodes(node.children) : ''

  switch (node.type) {
    case 'root':      return children
    case 'paragraph': return `<p>${children || '&nbsp;'}</p>`
    case 'heading':
      const tag = node.tag || 'h2'
      return `<${tag}>${children}</${tag}>`
    case 'list':
      const listTag = node.listType === 'bullet' ? 'ul' : 'ol'
      return `<${listTag}>${children}</${listTag}>`
    case 'listitem':  return `<li>${children}</li>`
    case 'link': {
      const url = node.fields?.url || node.url || '#'
      const newTab = node.fields?.newTab || node.newTab || false
      const target = newTab ? ' target="_blank" rel="noopener noreferrer"' : ''
      return `<a href="${escapeAttr(url)}"${target}>${children}</a>`
    }
    case 'quote':         return `<blockquote>${children}</blockquote>`
    case 'horizontalrule': return '<hr/>'
    case 'linebreak':     return '<br/>'
    case 'upload': {
      const value = node.value
      if (!value) return ''
      const mimeType = value.mimeType || ''
      if (mimeType.startsWith('image/')) {
        const src = escapeAttr(value.url || '')
        const alt = escapeAttr(value.alt || value.filename || '')
        const width = value.width ? ` width="${value.width}"` : ''
        const height = value.height ? ` height="${value.height}"` : ''
        return `<figure class="rich-image">
          <img src="${src}" alt="${alt}"${width}${height} loading="lazy"/>
          ${value.caption ? `<figcaption>${escapeHtml(value.caption)}</figcaption>` : ''}
        </figure>`
      }
      const filename = escapeHtml(value.filename || 'Download')
      const url = escapeAttr(value.url || '#')
      return `<a href="${url}" class="rich-download" download>${filename}</a>`
    }
    default: return children
  }
}

function escapeHtml(str: string): string {
  return String(str)
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&#039;')
}

function escapeAttr(str: string): string {
  return String(str).replace(/"/g, '&quot;').replace(/'/g, '&#039;')
}

Step 2: Use It in Astro Pages

---
import { lexicalToHtml } from '../../lib/lexical';

const { id } = Astro.params;
let item: any = null;

try {
  const PAYLOAD_URL = import.meta.env.PAYLOAD_INTERNAL_URL || 'http://localhost:3000';
  const res = await fetch(`${PAYLOAD_URL}/api/your-collection/${id}?depth=1`);
  if (res.ok) item = await res.json();
} catch(e) {}

if (!item) return Astro.redirect('/your-collection');

const bodyHtml = lexicalToHtml(item.body);
---

<div class="rich-content" set:html={bodyHtml} />

Step 3: The WHERE Query Format

This is the second most common silent failure in Payload REST API integrations. WHERE queries use bracket notation — not JSON encoding.

// Correct — bracket notation
`/api/pages?where[status][equals]=published`
`/api/pages?where[status][equals]=published&where[slug][equals]=about`
`/api/pages?where[status][equals]=published&sort=-createdAt&limit=10`

// Wrong — returns empty results silently
`/api/pages?where={"status":{"equals":"published"}}`
`/api/pages?where.status.equals=published`

Step 4: The Reusable Query Builder

Create src/lib/payload.ts:

const PAYLOAD_URL = import.meta.env.PAYLOAD_INTERNAL_URL || 'http://localhost:3000'

export async function fetchCollection(
  collection: string,
  params: {
    where?: Record<string, any>
    sort?: string
    limit?: number
    depth?: number
    page?: number
  } = {}
) {
  const parts: string[] = []

  if (params.where) flattenWhere(params.where, 'where', parts)
  if (params.sort) parts.push(`sort=${encodeURIComponent(params.sort)}`)
  if (params.limit) parts.push(`limit=${params.limit}`)
  if (params.depth !== undefined) parts.push(`depth=${params.depth}`)
  if (params.page) parts.push(`page=${params.page}`)

  const qs = parts.join('&')
  const url = `${PAYLOAD_URL}/api/${collection}${qs ? '?' + qs : ''}`

  try {
    const res = await fetch(url)
    if (!res.ok) return null
    return res.json()
  } catch(e) {
    console.error(`[payload] fetch failed: ${url}`, e)
    return null
  }
}

function flattenWhere(obj: any, prefix: string, parts: string[]) {
  for (const [key, val] of Object.entries(obj)) {
    if (val !== null && typeof val === 'object' && !Array.isArray(val)) {
      flattenWhere(val, `${prefix}[${key}]`, parts)
    } else {
      parts.push(`${prefix}[${key}]=${encodeURIComponent(String(val))}`)
    }
  }
}

// Ready-to-use helpers
export const getPublishedPages = () =>
  fetchCollection('pages', {
    where: { status: { equals: 'published' } },
    sort: 'title',
    limit: 50,
  })

export const getPageBySlug = (slug: string) =>
  fetchCollection('pages', {
    where: { slug: { equals: slug }, status: { equals: 'published' } },
    limit: 1,
    depth: 1,
  })

export const getPublicNotices = (limit = 10) =>
  fetchCollection('public-notices', {
    where: { status: { equals: 'published' } },
    sort: '-noticeDate',
    limit,
  })

export const getDepartments = (limit = 50) =>
  fetchCollection('departments', {
    where: { status: { equals: 'published' } },
    sort: 'name',
    limit,
  })

Step 5: Depth and Type Safety

Use depth=1 for most queries — it populates one level of relationships without ballooning response size. Use depth=2 only when you need data that is two relationships deep.

# Generate TypeScript types from your collections
cd payload
npm run generate:types

Copy payload-types.ts to your frontend for autocomplete and type safety:

import type { Page, Department, PublicNotice } from '../types/payload-types'

const page = data.docs[0] as Page
const content = page.content  // TypeScript knows this is Lexical JSON

Complete Series Recap

The Eight Undocumented Problems This Series Fills

When WAM DevTech built this stack in production, these were the problems that were not documented anywhere:

1. importMap population — no official docs on manual population for CI/CD environments
2. rsc exports — RscEntryLexicalField requirement is not in the Payload docs
3. RichTextCell removal — breaking change with no migration guide
4. Root layout restriction — the <html><body> hydration error is mentioned nowhere
5. serverFunction vs serverFunctions — prop name mismatch between versions
6. ALB rule priority ordering — /_next/* must precede the default rule
7. WHERE bracket notation — the REST API docs show examples but do not warn about JSON encoding failures
8. Health check matcher 200-404 — needed during Payload startup, not documented for ECS deployments

The complete working implementation of this architecture — deployed for Chippewa County, Michigan's government website in 5 days from an RFP document alone — is documented in the case study below.

Read the Chippewa County case study.