innerai.com vs Letterhead

Inner AI's substance is breadth of models under one login: Claude Sonnet 5.5, GPT 6, Gemini 4 Argon, Grok, Perplexity Sonar, DeepSeek, Llama, Qwen, QwQ, Mistral and the Brazilian Sabiá. The differentiators sit around that core — dozens of document templates, 250+ expert prompts sorted by department (marketing, HR, sales, finance, legal, academic), 50+ image generation across Luma, Leonardo, Ideogram and Nano Banana Pro, audio and slide generation, project folders, custom assistants for recurring writing, data analysis and contract review, and cross-device sync on web, iOS and Android. Pro adds Inner Academy's seven certified AI courses and live chat support seven days a week in Portuguese.

Letterhead's substance is governance and monetization of a newsletter portfolio. Studio sits on your existing ESP, with lockable global templates, a drag-and-drop editor, and approval flows routing every edition through editorial review. Suite adds unified audience view, segments, journeys and triggered flows. Penpal agents curate content, draft sections, segment audiences and queue sends, but publish waits on human approval. On the revenue side there is direct ad management, programmatic ads, house promotions, conversion CTAs and automated sponsor reporting, plus portfolio-wide analytics across audiences, brands and goals, and sending with dedicated IPs and automated warmup from Letterhead's own list.

These capability sets barely intersect. Inner AI generates content; Letterhead manages who approves, sends, measures and monetizes it at scale across titles.

Inner AI publishes its numbers. The Lite annual plan runs 12x R$49,90/mo, or R$99,90/mo billed monthly. The vendor's own pitch is comparative: five direct model subscriptions total roughly R$600 a month, so consolidation is the whole sale. Read the tier limits before you commit — Lite caps advanced-model usage at 120 messages a month while unlimited chat applies to fast models (Claude 5.5 Haiku, GPT 6 Instant, Gemini 3.5 Flash), and the unlimited plans carry fair-use throttling that matters to high-volume operations. Pro is where document analysis, web research, custom assistants and Inner Academy unlock. There is no documented API, so budget for seats in the web/desktop/mobile app, not for usage-based metering.

Letterhead does not publish pricing at all: it is a contact-sales, custom-quote product, and its own "not for" list flags teams that can't wait a day for that quote. Commercial logic is portfolio-based, so the number scales with titles, seats and revenue tooling rather than a per-seat list rate. It also stacks on top of whatever ESP you already pay for, so the real budget line is Letterhead plus your existing Mailchimp, Iterable, Braze, Salesforce Marketing Cloud or HubSpot contract — not a replacement for it. Expect a sales conversation scoped to titles and ad revenue.