CMS migration

Sanity → Astro

Move content, assets, authors, URLs, SEO, design, forms, permissions, integrations, and publishing operations from Sanity into Astro with an explicit exception ledger and evidence-based cutover.

Typical timeline12–30 business days55–110 hours active work

Statusneeds review

Source testedSanity documentation reviewed 2026-07-19

Destination testedAstro documentation reviewed 2026-07-19

Last reviewed2026-07-19

Sources2

Before you migrate

Should you make this move?

Both platforms have a case. Compare what you gain with what you give up before scheduling the cutover.

Current platform

Sanity

Reasons to stay

Content Lake, schema-as-code, and customizable Studio support sophisticated structured content
Editors get a purpose-built publishing workflow instead of raw files

Reasons to leave

GROQ, schema code, and custom editorial tooling demand engineering ownership
Themes, extensions, and content models add maintenance and portability constraints

New platform

Astro

What gets better

Content-focused sites ship very little client JavaScript by default
Managed deployments reduce infrastructure and release-management work

What gets worse

Repository-based publishing and custom integrations require engineering ownership
Runtime assumptions, platform services, and pricing models shape the architecture

Best of the move

Astro: Content-focused sites ship very little client JavaScript by default. This removes a major source-side concern: GROQ, schema code, and custom editorial tooling demand engineering ownership.

Worst of the move

What you lose: Content Lake, schema-as-code, and customizable Studio support sophisticated structured content. What you inherit: Repository-based publishing and custom integrations require engineering ownership.

01At a glance

Know the shape of the move.

Transfer outcome12 features audited

Clean0

Partial5

Manual5

Lost2

Mapping route9 of 9 fields have a destination path

SourceSanity9 mapped fields

Automatic1

Transform5

Manual3

Unsupported0

DestinationAstro9 supported paths

This timeline assumes

Up to 10 sites, 10,000 content items, and 25,000 public routes
The source remains publicly reachable until media and route verification passes.
Dynamic features outside the documented scope require an approved replacement.
The destination is built and reviewed on a private preview before DNS changes.
The migration team records evidence for every blocking verification check.

02Loss matrix

What survives the move.

“Partial” and “manual” are not footnotes. They are work that must be scheduled and verified.

Item	Outcome	Impact	What happens	Mitigation
Content, assets, authors, structure, public URLs, and metadata	partial	critical	Core content, assets, authors, structure, public urls, and metadata can move, but Sanity and Astro use different models, limits, identifiers, and import behavior.	Pilot every feature class, preserve source IDs, and reconcile accepted, transformed, rejected, and excluded items.
Themes, hosted applications, forms, memberships, integrations, and history	manual	critical	Sanity-specific runtime configuration and historical evidence do not become native Astro behavior through the core data transfer.	Inventory every active dependency, approve its destination disposition, and test the replacement before source writes stop.
Published posts and pages	partial	critical	Core titles and body content can move, but platform-specific blocks and metadata need review.	Compare every route and a stratified content sample.
Images and downloadable media	partial	critical	Exports can reference remote files instead of carrying verified local originals.	Copy originals, record hashes, and keep the source public until reconciliation.
Public URLs and redirects	manual	critical	Routing rules and slug behavior differ between the two platforms.	Create a source-to-destination URL registry and test every redirect.
Authors and permissions	partial	high	Bylines may move, but user accounts, roles, and credentials do not transfer safely.	Create destination users deliberately and assign least privilege.
Taxonomies and navigation	partial	high	Categories, tags, menus, and collection semantics rarely map one-to-one.	Approve a mapping and test archive, menu, and breadcrumb behavior.
SEO metadata and structured data	manual	critical	Titles, descriptions, canonicals, social cards, and schema require destination configuration.	Crawl both sites and block cutover on critical SEO differences.
Forms and submissions	manual	critical	Hosted form processing, spam controls, notifications, and submission history are platform-specific.	Export history and test each replacement from submission through durable receipt.
Analytics and historical reports	lost	medium	Historical platform reports do not become native destination history.	Export dated reports and annotate the analytics cutover.
Theme and visual presentation	lost	high	Source themes and design systems do not run on the destination platform.	Rebuild approved templates and compare screenshots at supported breakpoints.
Integrations and scheduled jobs	manual	critical	API keys, webhooks, embeds, and scheduled jobs remain connected to the source.	Inventory, replace, rotate, and test every production integration.

03Field and feature mapping

Where each thing goes.

Source	Destination	Method	Notes
Sanity post or page	Astro content item or page	transform	Preserve source ID and public URL.
Title	Title	automatic	Verify entities and Unicode.
Slug or path	Slug or path	transform	Preserve the public URL or create one redirect.
Rich body	Destination rich content	transform	Repair unsupported blocks and embeds.
Author	Destination user or byline	manual	Provision users before assignment.
Category or tag	Destination taxonomy	transform	Approve hierarchy and primary classification.
Featured image and media	Destination media	transform	Copy originals and preserve alt text.
SEO fields	Destination SEO fields	manual	Verify titles, descriptions, canonical, social data, and schema.
Form	Destination form or external handler	manual	Rebuild validation, consent, spam control, storage, and alerts.

04Before you begin

Make the move recoverable.

Backup procedure

Create the source-of-truth backup

Preserve Sanity data, configuration, and operating evidence before any destination write.

Export all available Sanity content and settings.
Crawl production for routes, metadata, schema, assets, forms, status codes, and integrations.
Capture themes, design tokens, screenshots, DNS, domains, users, redirects, analytics, and submissions.
Record counts and cryptographic hashes in an immutable manifest.

Proof to capture: A signed manifest reconciles every scoped record class, runtime dependency, export file, count, and hash.

Transformation · Crawler, spreadsheet, and content transformer

Content and route registry

Preserve public content and URL intent.

Inventory source values and exceptions.
Define explicit destination mappings.
Reject unmapped critical records.

Proof to capture: Save the input, output, command or tool settings, warnings, and final item counts.

Transformation · Checksum tool and schema validator

Asset and metadata normalization

Make media, taxonomy, and SEO deterministic.

Normalize encoding, dates, identifiers, and blanks.
Run a representative pilot.
Reconcile accepted, rejected, and transformed rows.

Proof to capture: Save the input, output, command or tool settings, warnings, and final item counts.

05Handle with care

The things most likely to hurt.

These are operating limits. Treat every “Stop if” condition as a blocked migration, not a suggestion.

Import

A successful import hides missing runtime behavior

criticalpossible likelihood

A page renders while forms, access, search, or integrations fail.

Consequence: Visitors lose content or business actions.
Mitigation: Test behavior, not screenshots alone.

Stop if: Any critical runtime path lacks durable evidence.

Cutover

URLs or metadata change silently

criticalpossible likelihood

The destination crawl has missing routes, redirect chains, or canonical differences.

Consequence: Traffic and search visibility regress.
Mitigation: Require a route and SEO diff before DNS changes.

Stop if: A critical route lacks one valid destination.

Cleanup

Remote media disappears after source shutdown

highpossible likelihood

Destination markup still loads source-hosted assets.

Consequence: Images and downloads break later.
Mitigation: Copy and hash every required asset.

Stop if: A critical asset depends on the source domain.

06Precise timeline

Do the work in this order.

Estimate forUp to 10 sites, 10,000 content items, and 25,000 public routes

Total elapsed12–30 business days

Active work55–110 hours

BufferAdd time for large exports, unsupported Sanity features, destination limits, identity exceptions, regulated data, or strict downtime requirements.

Days 1–3Inventory and decisions2–3 days

Days 3–5Backup and reconcile1–3 days

Days 5–12Map and pilot3–8 days

Days 10–20Final delta and switch1–5 days

Days 12–40Observe and close3–10 days

1
Days 1–3 · inventory
Inventory and decisions
6–12 hours active2–3 days elapsedOwner review waiting
- Inventory Sanity data, features, users, domains, and integrations.
- Approve scope, owners, mappings, and exclusions.
Depends on: Sanity and Astro administrator access
Stop / go checkpoint
Export?
Go when: Every critical item has an owner and disposition.
Stop when: Consent, billing, access, or system ownership is unclear.
2
Days 3–5 · backup
Backup and reconcile
5–10 hours active1–3 days elapsedExport processing waiting
- Create immutable exports and configuration evidence.
- Reconcile counts, totals, and hashes.
Depends on: Approved inventory
Stop / go checkpoint
Transform?
Go when: Source totals and export manifests agree.
Stop when: Any critical dataset or configuration is absent.
3
Days 5–12 · pilot
Map and pilot
10–35 hours active3–8 days elapsedDestination processing and review waiting
- Configure Astro and transform representative data.
- Run a pilot containing normal records and every critical edge case.
Depends on: Verified backup
Stop / go checkpoint
Scale?
Go when: Pilot mappings, behavior, access, and evidence pass.
Stop when: Any critical check fails or produces unexplained variance.
4
Days 10–20 · cutover
Final delta and switch
5–25 hours active1–5 days elapsedDNS, import, or sync propagation waiting
- Freeze production writes in Sanity.
- Apply the final delta, switch ownership, and run blocking checks.
Depends on: Passed pilot and approved rollback
Stop / go checkpoint
Open production?
Go when: Counts reconcile and one destination system owns production.
Stop when: A source writer remains active or a blocking check fails.
5
Days 12–40 · observe
Observe and close
3–18 hours active3–10 days elapsedOperating-cycle evidence waiting
- Monitor one complete operating cycle.
- Sign the verification report and close rollback only after stability.
Depends on: Verified cutover
Stop / go checkpoint
Close rollback?
Go when: No trigger occurs during the agreed observation period.
Stop when: Data, access, delivery, routing, or business results regress.

07The point of change

Cut over with a way back.

Go live

Cutover

Make Astro the only production system without losing the final Sanity delta.

Recommended window: A low-volume weekday morning with platform, data, DNS, and business owners available.

Freeze production writes and scheduled actions in Sanity.
Export, transform, and reconcile the final delta.
Apply the approved delta to Astro.
Switch domains, forms, integrations, sending, or sync ownership as applicable.
Run every blocking verification check and keep the source intact.

Proof to capture: Astro owns production, totals reconcile, and every blocking check has durable evidence.

Return to safety

Rollback

Return production ownership to Sanity without losing destination-era changes.

Deadline: Within seven days and before source data, plans, credentials, domains, or billing are changed.

Stop new writes and scheduled actions in Astro.
Restore the prior Sanity routing, forms, integrations, sending, or sync ownership.
Export the Astro post-cutover delta.
Review and apply safe destination-era changes to Sanity.
Run the same blocking checks against the restored source.

Proof to capture: Sanity again owns production with current data and no duplicate destination action.

Rollback immediately when

Unexplained critical count or value variance
Missing or exposed critical data
Duplicate production action
Failed access, routing, delivery, or integration check
A critical feature has no safe destination replacement

08Verification report

Prove the migration worked.

Every blocking check must pass. Capture the evidence before cleanup begins.

ID	Check	Method	Expected result	Evidence
`V-01`Blocking	URL disposition	Crawl every source URL.	One 200 destination or one-hop permanent redirect.	Crawl diff.
`V-02`Blocking	Record and field reconciliation	Compare counts and stratified records.	Every scoped item and critical field maps.	Content manifest.
`V-03`Blocking	Binary independence	Compare URLs, hashes, sizes, and source-domain requests.	No required asset depends on the source.	Asset report.
`V-04`Blocking	Metadata and index control	Compare titles, descriptions, canonicals, robots, social data, and schema.	Approved parity with no accidental noindex.	SEO diff.
`V-05`Blocking	Submission lifecycle	Submit every form and upload path.	Validation, storage, consent, notification, and response pass.	Submission IDs.
`V-06`Blocking	Restricted content	Test anonymous and authorized roles.	No restricted content leaks.	Access matrix.
`V-07`	Responsive templates	Compare key pages at approved breakpoints.	Content and interactions meet acceptance.	Screenshot set.
`V-08`Blocking	Single source of truth	Inspect publishing and integrations in both systems.	Astro alone owns production.	Operating inventory.

09Post-migration cleanup

Remove the scaffolding safely.

Safe after: One complete operating cycle, at least seven stable days, and owner sign-off on every blocking check.

Create final Sanity exports and archive verification evidence.
Revoke temporary credentials, API keys, webhooks, and elevated roles.
Remove obsolete embeds, forms, jobs, integrations, and DNS records.
Keep the source intact through the approved retention window.
Cancel paid plans only after billing, legal, and recovery review.
Schedule the next Astro backup, access, and migration-playbook review.

Sources and maintenance

Built to be reviewed.

Tested 2026-07-19. Next scheduled review: 2026-10-19.

Sanity: official migration documentationAccessed 2026-07-19
Astro: official migration documentationAccessed 2026-07-19

Know the shape of the move.

This timeline assumes

What survives the move.

Where each thing goes.

Make the move recoverable.

Create the source-of-truth backup

Content and route registry

Asset and metadata normalization

The things most likely to hurt.

A successful import hides missing runtime behavior

URLs or metadata change silently

Remote media disappears after source shutdown

Do the work in this order.

Inventory and decisions

Export?

Backup and reconcile

Transform?

Map and pilot

Scale?

Final delta and switch

Open production?

Observe and close

Close rollback?

Cut over with a way back.

Cutover

Rollback

Prove the migration worked.

Remove the scaffolding safely.

Built to be reviewed.