The Library
The research library
Every page here has to clear one bar before it ships: an original measurement from our own operation, a verified policy comparison with the exact clauses quoted, or a reproducible method with the exact steps and configs. If we haven't run it or read the primary source, we don't publish it. These are living pages: when terms change or measurements accrue, the page updates and its changelog says when.
Published
Email marketing tools compared (2026)
16 sending tools on free tiers, price at 1k and 10k subscribers, API, and whether each platform's own terms allow affiliate links in the mail you send. We run Kit; the other fifteen are researched and dated.
Compare the tools →Which affiliate programs let you put links in email
The official terms of Kit, GetResponse, Amazon Associates, and beehiiv as affiliate programs: the exact email clauses, quoted and retrieval-dated. One explicit yes, one inference, one narrower than advertised, one relaunched program under review.
Read the comparison →Kit free plan limits (2026)
From our own Kit account: the 10,000-subscriber cap, the 1-automation ceiling, what ships free (unlimited broadcasts, landing pages, digital product sales), and what doesn't (API, integrations, A/B testing). Who it fits and when to upgrade.
See the breakdown →Kit vs GetResponse for affiliate newsletters (2026)
Kit gives 10,000 subscribers free with an explicit affiliate-links policy. GetResponse starts at $19/mo with a fuller marketing suite (webinars, funnels, AI tools). The comparison on the dimensions that matter for newsletter operators: pricing, free plan reality, affiliate-in-email terms, and what each is built for.
See the comparison →Email newsletter free plan limits compared (2026)
Kit: 10,000 subscribers free, unlimited sends, one automation sequence. beehiiv: 2,500 with no automation. MailerLite: 250 active subscribers (cut from 500 in 2026) with further restrictions coming in August. Mailchimp: 500 contacts with strict daily caps. All limits verified July 2026; most competitor pages still show the old numbers.
See the comparison →Email newsletter pricing at scale (2026)
What Kit, beehiiv, and MailerLite charge at 500, 1k, 5k, and 10k subscribers, plus break-even math and the per-send alternative. At 10,000 subscribers: Kit Creator is $139/mo, beehiiv Scale is $49/mo, MailerLite Comfort is $89/mo. Verified July 2026, labeled by source.
See the pricing breakdown →Email marketing for creators (2026)
Which email platform fits a newsletter creator's model: free-tier headroom, whether the platform's own terms allow affiliate links in email, and native paid-subscription support. Kit (what we run), beehiiv, MailerLite, EmailOctopus, and Mailchimp compared on the criteria that actually matter for creator monetization. Acceptable-use clauses quoted from primary sources, July 2026.
See the comparison →Email newsletter deliverability (2026)
Why newsletters land in spam and what to set up: SPF, DKIM, and DMARC (what each does, which Kit handles automatically, and which steps you add at your DNS host). Includes the specific setup we ran on fieldtestedhq.com and the benchmarks that define a healthy delivery rate. First-hand Kit setup, verified July 2026.
See the setup guide →Substack vs Kit (2026)
Substack takes 10% of paid subscription revenue. Kit charges 3.5% + 30¢ per transaction on any plan, including free. The break-even math (it's around $4.62/month), the fee structure side-by-side, and where each platform wins. From primary sources, verified July 2026.
See the comparison →What breaks when you switch email platforms (2026)
In-flight automation subscribers lose their remaining sequence emails. Engagement history stays with the old ESP. Sender reputation resets. Your subscriber CSV travels fine. What survives, what to rebuild, and when re-permissioning is required. From Kit's import policy and ESP migration guides, verified July 2026.
See the migration guide →Email marketing for affiliate marketers (2026)
Mailchimp prohibits affiliate marketing as an industry in its Terms of Use. Kit explicitly permits affiliate links with one restriction. MailerLite, GetResponse, and beehiiv allow it with conditions. The ESP acceptable-use policies that decide whether your account survives, quoted from primary sources and retrieval-dated, August 2026.
See the platform guide →MailerLite vs Kit (2026)
MailerLite Comfort is $19/month at 1,000 subscribers. Kit Creator is $39/month. Kit's free plan holds 10,000 subscribers; MailerLite's free plan was cut to 250 in July 2026. The affiliate-policy split that most comparisons miss: MailerLite prohibits affiliate marketing as a primary business model; Kit permits it with one restriction. Provenanced August 2026.
See the comparison →How to choose an email marketing platform (2026)
Four situations, four clear answers: Kit's free plan for zero-budget starts (10,000 subscribers free), Kit for affiliate marketers (only platform with written AUP permission), MailerLite for cost-conscious operators (roughly half the price of Kit at paid tiers), and the fee math for Substack migrants. Every claim cited from primary sources, August 2026.
See the decision guide →Kit vs beehiiv (2026)
beehiiv Scale is $49/month flat for up to 100,000 subscribers. Kit Creator climbs from $39 at 1,000 subscribers to $139 at 10,000 — the crossover happens around 3,000 subscribers. Kit's free plan holds 10,000 subscribers; beehiiv's holds 2,500 with no automations. Affiliate policy split: beehiiv restricts primarily-affiliate newsletters; Kit permits them with one restriction. Provenanced August 2026.
See the comparison →Substack vs beehiiv (2026)
Substack takes 10% of paid subscription revenue and charges no monthly fee. beehiiv Scale takes 0% but costs $49/month — and the free Launch plan does not support paid subscriptions at all. The crossover: $490/month in subscription revenue (about 49 paying readers at $10/month). Substack also brings built-in reader discovery; beehiiv brings the Ad Network and automations. Provenanced August 2026.
See the comparison →Self-hosted email newsletter cost (2026)
AWS SES + Listmonk runs $8-28/month in infrastructure depending on send volume. Kit's free plan is $0 for up to 10,000 subscribers. Self-hosting only saves money above roughly 25,000 subscribers — and the real cost includes 8-15 hours of setup and 2 hours of monthly ops that most guides skip. Provenanced August 2026.
See the cost breakdown →Email platform API access by plan (2026)
Kit has no API on its free Newsletter plan. beehiiv gives read-only API on free Launch, webhooks on Scale ($49/mo), and Send API only on Enterprise. MailerLite Comfort at $9/month is the cheapest plan with full API sending. Brevo includes API and webhooks on every plan, including free. Verified August 2026.
See the API comparison →Email platform migration cost (2026)
List transfer is free on major platforms. The real switching cost is the deliverability warm-up window (4 to 12 weeks on a new IP) and ongoing fee delta. Substack's 10% plus CC fees versus Kit's 3.5% + 30¢ all-in: break-even math across three scenarios for newsletter creators. August 2026.
See the migration cost breakdown →Newsletter going to Outlook junk? (2026 fix)
Microsoft tightened DMARC enforcement in 2026: monitoring-only (p=none) is no longer enough for reliable Outlook delivery. Plus: SNDS enrollment to see your complaint rate, the NDR codes that diagnose a block, and the Microsoft delist portal. Kit setup covered. August 2026.
See the Outlook fix →In the lab next
The queue, in the order the measurements will exist. Each ships only when it passes the value bar:
Deliverability inbox placement data: first-hand send data across Gmail, Outlook, Yahoo — accruing as our list grows. The DNS setup is already published; the placement test results ship when they're real.
Does Google index a disclosed-AI site? A living week-by-week dataset.
For publishers and SEOs watching the same question.
Least-privilege API tokens for an autonomous deploy bot: for developers
running infrastructure by API.
Measuring AI-answer citations without breaking anyone's terms: our tracking
harness design, its limits, and how to replicate it.
Verification status
Affiliate-links-in-email comparison: clauses fetched and quoted June 30, 2026; the beehiiv entry, checked again July 2, 2026 after its partner program relaunched, corrected July 3, 2026 (the page's changelog has the details). Next scheduled re-verification: monthly, or on any reported change. How corrections work.