The variable engine, the soul layer, and a few honest opinions.
Six features carry the weight. Everything else is house-cleaning. Below: each in plain English, with the one trade-off we made to keep it sharp.
The variable engine.
The thing under the hood. Every Oh Boiler template is structured text with named variables — {first_name}, {specific_detail}, {soul_paragraph}. Fill the variables once per recipient. The structure stays. The soul gets typed in.
Variables can be required or optional, scoped per recipient or per template. They remember themselves: if you've used the recipient before, last time's values pre-fill, ready to keep or edit.
- — Claude Opus 4.7
- — Claude Sonnet 4.7
- — GPT-5
- — GPT-5 mini
- — Gemini 2.5 Pro
- — Llama 4 405B
- — Mistral Large 3
- — Cohere Command R+
↑ pick the voice that fits the letter.
AI fill assist.
Paste the job description, the LinkedIn profile, the customer's last support thread — Oh Boiler drafts a candidate for any variable. You always edit before sending. The model never sees the rest of your library, just the prompt you explicitly send.
Eight models available on Pro. Pick the one whose voice fits the letter: Claude when you want warmth, Gemini when you want concision, GPT-5 when you want a fast first draft. Switch per template, per variable.
Per-recipient memory.
Oh Boiler remembers what you wrote to whom. Open a template for someone you've written to before and last time's variables pre-fill. The "what we last discussed" line writes itself. The "still laugh about the kayak trip" line is still there because you wrote it once, three months ago.
A small thing that, over a year of writing, saves more time than any other single feature. Per-recipient memory is the difference between a template tool and a writing companion.
Memory snapshot
Three voices, set once.
- — House — clear, concise, warm.
- — Formal — slower cadence, longer sentences.
- — Personal — first-person, contractions, occasional dash.
Brand voice presets.
Define your voice once — three presets per workspace — and every template renders to that voice when you switch. A two-person team picks House for client letters and Personal for internal updates and never has to think about it again.
The Team plan adds custom presets and SSO so a thirty-person company writes in a consistent voice across all client-facing letters, without writing thirty different versions of the welcome email.
Where it lives, not where you visit.
Oh Boiler is not a tab you visit. It's a layer between you and the writing apps you already use. Browser extension for Gmail and Outlook. Native shortcut for Notion. Slack-native /template command on the Team plan.
Open the template picker with one keyboard shortcut from inside the app you're already in. Fill the variables. Hit send. The whole experience takes seven seconds longer than not using a template, and saves you eight minutes per letter.
Six apps. One shortcut.
- — Gmail (Chrome, Firefox)
- — Outlook web
- — Apple Mail (macOS, beta)
- — Notion (text shortcut)
- — Slack (/template, Team plan)
- — Linear (comment macro, beta)
Shortcut: ⌘ + Shift + B
Auto-send.
Several investors have asked. Several customers have requested. We will not build it. A template tool that sends without you in the loop is a spam tool with a story. Oh Boiler will always require one click from you, at the end, after you've read the filled-in letter.
The boilerplate gets boring; the click should not. The click is where you, the writer, certify that the letter is one you'd be proud to have written by hand. We keep the click. The click stays yours.
Save the structure. Keep the soul.
Five templates free. The variable engine. Three voice presets. The Gmail extension. No card.
Start free