The AI writing apps you can pay for once on a Mac are WunderType, RewriteBar, Kerlig, BoltAI, and Summon’s lifetime license. “Once” does not mean the same thing on each of them. The difference is how long updates are included, and who bills the model.
Grammarly and Raycast AI are subscriptions, so they are not in this list. Apple Writing Tools are free with macOS, which is a different kind of free. Each price below was on that product’s site on October 27, 2026.
What you actually pay
| App | You pay | Updates | Model bill |
|---|---|---|---|
| WunderType | $8.99 once | Sold as a one-time purchase | OpenAI or OpenRouter tokens, or no bill for on-device |
| RewriteBar | $29 once for one device, or $59 for three | Unlimited app updates. Gateway on the $59 plan is one year | Included credits, or your own key |
| Kerlig | Basic $49 once | Confirm how many Macs and how long updates last | Your provider’s tokens |
| BoltAI | Essential $79 | One year of updates. The version you have keeps working after that | Your provider’s tokens |
| Summon lifetime | $79.99 | Every future update, on up to three Macs | Your provider’s tokens |
Do pay-once licenses include updates?
Not in the same way. WunderType’s page sells the app once and does not describe an update cutoff. RewriteBar’s paid licenses say unlimited app updates, with Gateway on the higher license limited to a year. BoltAI includes one year of updates, then the version you already have keeps working and cloud sync pauses until you renew. Kerlig’s Basic license is one-time, and the update window should be confirmed on their page before you buy. Summon’s lifetime license includes every future update.
Is Summon pay once?
Summon is pay once on the lifetime license, which is $79.99. The same app also sells a weekly plan at $1.99 and a yearly plan at $29.99, each with a 72-hour trial. The lifetime plan has no trial. Every plan has a 14-day refund. Provider tokens are never included. The current numbers are on the pricing page.
The lifetime license is the one to compare with BoltAI’s $79 Essential plan. The sticker is almost the same. BoltAI includes a year of updates and a much wider model list, including local models. Summon includes updates from then on, and it only runs a command on selected text. There is no on-device model.
Which pay-once app should you buy?
Buy WunderType if $8.99 and an in-place correction are the whole decision. The WunderType alternative covers what that app does not do.
Buy RewriteBar if you want a one-time license with a credit pool, or a local model, and you are fine with the default call going through their server. See the RewriteBar alternative.
Buy Kerlig or BoltAI if you want the workbench: many providers, local models, and a chat you come back to. See the Kerlig alternative and the BoltAI alternative.
Buy Summon’s lifetime license if the job is a command on text you already selected, you want updates included after the first year, and you already have a key for OpenAI, Anthropic, Google Gemini, or xAI. Subscriptions such as Grammarly and Raycast AI sit in the wider shortlist, not in this one.