iOS · Shipped

The message you've been avoiding?
Replied in 20 seconds.

ReplyGhost writes the reply for you. Paste what you got, pick the situation, get three human options you can actually send. No account, no tracking, messages never leave your device.

See it in action → How it was built

PlatformiOS 17+

Built solo in~3 weeks

AI spend~$508

EngineOpenAI (BYOK)

The problem

You have a message you can't reply to.

The text from two weeks ago. The Slack you meant to answer yesterday. The apology you've been rewriting in your head since Tuesday. Every hour it sits there, the harder it gets to send — and "sorry for the late reply" stops working by day three.

ReplyGhost is the 20-second way out. Paste the message, tell it who it's from and what you want to say, and it writes three options — warm, neutral, firm, or playful. Copy one. Send. Move on with your life.

What's in the box

Built for the avoided-reply.

Six intents that cover 90% of the conversations people actually avoid. Four tones. Zero bloat.

🙏

Apology

When "sorry for the late reply" won't cut it anymore. Three ways to actually own it.

✓

Confirm

Lock in plans, receipt of info, or a yes — without sounding like a robot.

Decline

Turn something down without scorched earth. Polite, final, not a 4-paragraph excuse.

⏱

Delay

Buy time honestly. "I'll get to this by Friday" beats going silent for 8 more days.

📅

Reschedule

Move the thing without triggering a 14-message back-and-forth.

💬

Casual

The "send this in 10 seconds" option. For texts that don't need a strategy.

The product

Five screens, one job.

Paste → pick → pick → get 3 replies → copy. That's it. No accounts, no feeds, no notifications.

How it was built

Solo · 3 weeks · ~$508 in AI spend.

ReplyGhost was built end-to-end by one person with a laptop and a Claude Code subscription. Here's the honest stack.

$508

Claude Code spend

Full build — spec, Swift code, tests, App Store assets

77M

Tokens processed

94% served from prompt cache

Intents shipped

Covers the 90% of avoided messages

Cofounders, employees, freelancers

Built solo, shipped solo

Frontend

Native iOS · Swift + SwiftUI. Xcode archive on disk, ready for App Store review.

OpenAI GPT-4-class model via BYOK. User pastes their own API key — no server, no middleman, no data retention.

Offline

Built-in reply template library for users without an API key. Works airplane-mode on day one.

Privacy

Zero analytics, zero accounts, zero server. Messages go from your keyboard → OpenAI → screen. Nothing touches my infra.

Build pipeline

Spec, Swift modules, unit tests, screenshots, App Store copy — all authored in Claude Code using Opus 4.6 + Sonnet 4.6 for cheaper tasks.

Cost per feature shipped

~$85 average, including all retries and reruns. The most expensive single feature was the onboarding flow at $142.

Want the playbook?

I write about how I build things like this — AI agents, shipped products, the actual cost. No fluff.

Follow along →

The message you've been avoiding?Replied in 20 seconds.