Sanity Check v3 Platform Decision

The question

Which newsletter platform (Substack vs Ghost vs Beehiiv vs ConvertKit/Kit) best fits a Sanity Check v3 revival targeting 500-2000 paid subs over 18 months, given priorities of (a) embed/SEO friendliness for sc.raydata.co, (b) sponsorship-revenue tooling, (c) zero migration friction from the existing 21-issue archive?

Context: SC v3 has been Blocked for 16 days awaiting this decision. The 21-issue archive currently lives on Substack at sc.raydata.co. RDCO wants to migrate to its own subdomain for SEO ownership and brand independence.

What we already know (from the vault)

[[01-projects/newsletter/revival-strategy]] — the existing strategy doc already flags this as Open Question #1, leaning Beehiiv ("better analytics, referral tools, and sponsor marketplace") with Substack as the speed alternative. Ghost and Kit were not seriously evaluated.
[[01-projects/newsletter/index]] — the 21 archived issues are explicitly the asset to preserve; the index page already brands the archive at sc.raydata.co.
[[01-projects/newsletter/sc-relaunch-essay]] — the relaunch piece is drafted and platform-agnostic; nothing in it pins a platform decision.
[[06-reference/2026-04-04-authority-nathan-barry]] — Barry's Authority (4th ed.) is the "list = business asset" anchor; he is the founder of Kit, so the bias is logged but doesn't outweigh fit.
[[06-reference/2026-04-13-cole-100k-paid-newsletter-playbook]] — Cole's $100K playbook implies sponsor-driven monetization layered on a paid tier; he runs on Substack and ConvertKit but explicitly notes the platform is interchangeable once the audience is owned.
[[06-reference/2026-01-27-ship30for30-substack-newsletter-guide]] — Ship30for30's case for Substack is discovery network, not SEO. They acknowledge SEO is weak and the founder needs an existing social audience either way.
[[06-reference/concepts/open-knowledge-sharing]] — the editorial philosophy rules out paywalls. Sanity Check is free-content, sponsor-monetized. This makes "paid subs" in the brief's question a slight misframe — the 500-2000 number is the list-size milestone that unlocks sponsor pricing per the revival-strategy timeline.

What the web says

Platform	Self-hosted?	Sponsorship native?	SEO-friendly	Migration ease (from Substack)	Pricing (2026)	Best for
Substack	No (substack.com or $50 one-time custom domain)	Boost network + reader-tier subscriptions; no native ad marketplace	Weak — no meta/title/URL customization, substack.com domain bias	Native (you're already there)	Free + 10% rev share on paid subs	Network discovery for writers without a list
Ghost (Pro)	Yes (or self-host OSS)	Native paid subs, sponsorship blocks, Stripe direct, no platform fee	Excellent — XML sitemaps, canonical tags, full meta control, own domain	Official Substack importer (posts + free + paid CSV; Stripe must be reattached); free white-glove migration on annual plans	Starter $9/mo, Creator $25/mo, Team $50/mo (annual; up to 500 / 1k / unlimited contacts)	SEO + ownership + design control
Beehiiv	No	Native Ad Network + Boosts (paid recommendations) + native paid subs	Good — meta titles, descriptions, URL slugs, custom domain on paid	Beehiiv-run import handles 500K+ subs; custom domain DNS in 24-48h	Launch $0 (≤2.5k subs, no custom domain), Scale $49/mo, Max $99/mo, Enterprise custom; 0% on paid subs, ~8% on Boosts	Growth-first newsletters monetizing via ads/boosts
Kit (ConvertKit)	Hosted; supports custom domains for landing pages	Sparkloop-integrated paid recommendations (23.5% Kit cut, $2k min); no native sponsor marketplace; manual sponsor placements via templates	Limited — landing pages and forms indexable, but no first-class blog/archive SEO	API-based import; no white-glove path from Substack archive specifically	Free ≤10k subs (Newsletter), Creator from $25/mo, Creator Pro from $50/mo (scales with list size)	Course/funnel sellers with a product ladder

Notes:

Substack's $50 custom-domain fee gets you sc.raydata.co, but every page still renders from Substack's template; canonical URLs and indexable archive structure remain Substack-controlled.
Ghost's Substack importer brings posts, free subs, and paid subs, but Stripe must be reconnected and Substack continues collecting 10% on legacy paid subs until those subscribers re-confirm. For Sanity Check this is moot — there are no paid subs to port.
Beehiiv's free tier does not include custom domains; sc.raydata.co requires Scale ($49/mo) or above.
Kit's archive story is its weakest point — it's an email tool first; the public-facing newsletter site is essentially landing pages, not a SEO-optimized post archive.

Convergences and contradictions

Convergences across vendor-neutral sources:

Ghost is consistently rated highest for SEO and design control (own-domain, semantic markup, sitemaps).
Beehiiv is consistently rated best for built-in growth + sponsorship tooling (Ad Network, Boosts).
Substack is consistently rated best for discovery but worst for SEO and platform independence.
Kit is consistently rated as the wrong tool for someone whose product is the newsletter; its strength is automating funnels around a paid digital product.

Contradictions / vendor bias to flag:

Beehiiv-published comparisons (beehiiv.com/comparisons/*) downplay Ghost's SEO lead and overstate Beehiiv's sponsor revenue potential at small list sizes — the Ad Network meaningfully pays only above ~10k engaged subs.
Ghost's own comparisons downplay the operational lift of running the Substack-to-Ghost migration with active paid subs (the Stripe handoff is genuinely fiddly per the official docs). For SC v3 with zero existing paid subs, this objection evaporates.
The vault's own [[01-projects/newsletter/revival-strategy]] recommendation (Beehiiv) was made before priority (a) — SEO ownership at sc.raydata.co — was elevated to a top-three constraint. That tilts the answer.

Synthesis for RDCO

Recommendation: Ghost (Pro), Creator plan, on sc.raydata.co.

The three stated priorities resolve cleanly when you score them honestly:

(a) Embed/SEO friendliness for sc.raydata.co. Ghost wins this outright. It serves your archive from your domain with full control of titles, meta descriptions, canonical URLs, slugs, sitemaps, and structured data. Beehiiv is a respectable second (custom meta + slugs on paid plans), Substack is disqualified (the $50 custom domain is cosmetic — the platform still owns rendering, schema, and discovery surface), and Kit isn't really competing here at all. For a brand whose stated thesis is "fundamentals first" and whose growth flywheel includes evergreen archive issues being indexed (per the revival-strategy Phase 3 plan), giving up SEO ownership to either Substack or a Beehiiv-rendered archive trades the most durable asset Sanity Check has — the 21-issue back catalogue and whatever is written next — for short-term convenience.

(b) Sponsorship-revenue tooling. This is the priority that looks like a Beehiiv argument and isn't. The revival-strategy monetization timeline starts sponsor outreach at 1,000 subs ($200-500/issue) and raises rates at 2,500 subs ($500-1,000/issue). At that scale, sponsorship is a direct-sold, founder-relationship business, not a marketplace business. Beehiiv's Ad Network and Boosts are optimized for the "I'd like passive ad revenue without selling" creator — they pay meaningfully only above ~10k engaged subs and they take a cut. Ghost lets you place sponsor blocks in any template, run direct invoicing through Stripe, and keep 100% of the revenue; this is a better fit for Sanity Check's positioning (curated, vendor-skeptical) where sponsor selection is itself a brand signal. The Beehiiv pitch is for a different business — high-frequency, broader-audience, ad-dense newsletters.

(c) Zero migration friction. Ghost has the official Substack importer that handles all 21 posts plus the free subscriber list automatically; no paid subs exist, so the Stripe complication is not a factor. Free Ghost(Pro) white-glove migration is available on annual plans. Beehiiv's import is also strong but requires reconfiguring the custom domain DNS (you already control sc.raydata.co so this is one-day work either way). Both clear the "zero friction" bar against the existing Substack archive. Kit has no first-class Substack archive importer.

What the founder is accepting by picking Ghost:

$300/yr (Creator annual) cash cost vs Substack's $0-floor — but you keep 100% of any future sponsor revenue, which pays for itself at one $200 sponsor placement.
Loss of Substack's network discovery surface — but every vault doc on growth (Ship30for30, Welsh, Cole) says social-driven distribution is the actual engine, not Substack recommendations, especially for a B2B technical audience that doesn't browse Substack natively.
Slightly more setup work than staying on Substack — a one-time cost paid in the first week.

This unblocks the 16-day-stale task with a single command: provision Ghost(Pro) Creator on annual, point sc.raydata.co at it, run the Substack importer, ship the relaunch essay.

Open follow-ups

Should the founder pick the Ghost(Pro) Creator tier at $25/mo or self-host Ghost on a $5 droplet to save ~$240/yr? (Self-host adds ops surface; probably not worth it at this stage.)
What's the URL redirect plan for the Substack /p/ permalinks so existing inbound links don't 404? (Ghost docs note this is a manual step.)
Does the founder want a paid tier at all, or stay 100% sponsor-monetized per [[06-reference/concepts/open-knowledge-sharing]]? (The brief's "500-2000 paid subs" framing should be reconciled with the strategy doc's free-content stance.)
Should the relaunch publish from sc.raydata.co (preserves archive continuity) or raydata.co/sanity-check (consolidates SEO under main domain)? Subdomain wins for brand independence; subfolder wins for domain authority.
What sponsor outreach CRM (Notion, Airtable, plain Stripe) do we want set up before hitting the 1k-sub milestone, so we're not scrambling?

Sources

Vault:

/Users/ray/rdco-vault/01-projects/newsletter/revival-strategy.md
/Users/ray/rdco-vault/01-projects/newsletter/index.md
/Users/ray/rdco-vault/01-projects/newsletter/sc-relaunch-essay.md
/Users/ray/rdco-vault/06-reference/2026-04-04-authority-nathan-barry.md
/Users/ray/rdco-vault/06-reference/2026-04-13-cole-100k-paid-newsletter-playbook.md
/Users/ray/rdco-vault/06-reference/2026-01-27-ship30for30-substack-newsletter-guide.md
/Users/ray/rdco-vault/06-reference/2026-02-13-ship30for30-newsletter-guide.md

Web: