Contentful CMS

Project config, content types, and API keys: cms-config.md. Docs: https://www.contentful.com/developers/docs/

Gotchas

• Never migrate master directly. Create a sandbox environment, migrate there, validate, then promote or re-run against master in a maintenance window.
• Rollback is recreate, not undo: delete the sandbox, re-clone from master, re-run a corrected migration. Reverse migrations only work for additive schema changes.
• Links are not resolved by default — REST needs include (link resolution depth); GraphQL resolves nested selections but each level costs query complexity.
• Use sys.publishedAt as the cache-invalidation key.
• Prefer typed content types over JSON fields, and attach validations to every required field — Contentful will not enforce shape otherwise. Uniqueness must be declared explicitly: .validations([{ unique: true }]).
• Reference fields need an explicit linkContentType validation or any entry type can be linked: blogPost.createField('author').type('Link').linkType('Entry').validations([{ linkContentType: ['person'] }])

Migration command

contentful space migration --space-id <SPACE_ID> --environment-id sandbox migration.js

Migration scripts export function (migration) { ... } and use createContentType / createField / displayField.

Post-migration validation

1. Query a representative sample of affected entries; assert required fields and unique constraints hold (exit non-zero on a miss).
2. Build the site against sandbox content to catch render-time failures.
3. Run integration tests covering the modified content types.