Launch HN: April (YC S25) – Voice AI to manage your email and calendar

Hi HN, we’re Neha and Akash from April (https://tryapril.com). We are building an AI executive assistant to help you get through emails and manage your schedule, hands-free while you drive to work, or whenever else you prefer voice interaction.

Here's a demo: https://www.youtube.com/watch?v=ISKwEyuQQEo#t=50

...and here's a second one showing more complex use cases: https://www.youtube.com/watch?v=P8APprJ3-eY.

While driving 40 mins daily from SF to Berkeley, my inbox would flood to 30+ emails and I'd have back-to-back meetings lined up. I'd reach work already behind, then spend another hour just catching up. We figured with recent advances in voice AI, we could solve this dead time problem and start doing things on the go.

You can just speak to April and it can:

- Summarize important emails and flag what needs attention

- Send replies that I dictate (it handles the formatting and tone)

- Review my calendar and reschedule meetings on the fly

- Pull context from email threads for each meeting

- Archive/organize emails into folders

April is built using Deepgram for STT. Eleven Labs for TTS - built on top of LiveKit. We built our own MCP (Model Context Protocol) servers for Google integration, which handle auth, rate limiting, and maintain conversation context across email threads.

The most interesting part has been optimizing for lowest latency given we are a tool call heavy application. We are also trying to optimize the interruption handling and turn taking to make it feel more natural.

April is available on the AppStore (iPhone/iPad). You can try us out here https://apps.apple.com/us/app/april-ai-executive-assistant/i...

Free 3-day trial, then $14.99/mo. We'd love feedback on: Which email /calendar workflows are most painful for you? What tools beyond Gmail & Google calendar would be most valuable with a voice interface?

We’ll be in the thread all day to answer any questions, share more technical details and learn what would make April most useful to you. Comment away!

Definitely seems like it could be useful, but I'd be worried with giving AI write access to emails.

Is there a good audit trail of exactly what actions it takes at each step? I'd personally be worried about leaking proprietary or otherwise private information this way, or having it hallucinate information when it sends out emails potentially causing catastrophic issues.

vedhsaka · 4 months ago

Valid concern - April does not write emails for you unless you specifically ask for it. Users usually dictate what they want to reply.

But do you think a 'safe mode' - where April does only non destructive operation like read/summarize/draft/move emails to a folder would help you build trust?

It's in our pipeline - we can prioritize it to mitigate that fear.

zacharycohn · 4 months ago

I started building basically April last week. I have a "safety" toggle in my app. If it's on, there's a "Review Actions" tab that any write or destructive actions go to. Then when I'm done dictating/commuting/whatever, I open the Review tab and go through the actions (add this calendar event, send this text message, reply to this email, etc) one by one - it sort of works like a checklist.

Feel free to take the idea, if it's helpful. No credit/rights necessary. Y'all are much farther along than I am and if you come out with an Android app I'll probably end up a customer!

pavel_lishin · 4 months ago

> April does not write emails for you unless you specifically ask for it.

What if it thinks you asked for it?

tryitnow · 4 months ago

Yes, a safe mode would be great. I think it's a "nice to have" for a lot of early adopter (type of people who read HN), but it will be a "must have" more corporate types (a much bigger market).

kitchi · 4 months ago

Absolutely, having the AI agent write out a draft and leave it there, or better yet grant it read-only access to my email and have it draft email responses and store it somewhere else where I can retrieve it would be fantastic.

AI is still not at the point where I am comfortable letting it run free with my email, but a draft that I can read over and make changes to before sending it out is a game changer.

jFriedensreich · 4 months ago

Its the most frightening naive reply i could imagine, if you can ask for it, it can hallucinate you asking for it or it can get prompt injected you asking for it. for voice only agents without UI approval process the only way is to have a separate clean room permission agent that does only get absolute safe context not even aggregate email titles. also for emails its impossible to design a safe agent that does any sort write action after reading anything in a mailbox because the mailbox is by definition tainted third party data and personal sensitive at the same time. even moving to a folder without can be used for attacks by hiding password reset notification mails etc.

smt88 · 4 months ago

Safe mode is absolutely necessary. I'd never let an LLM do things for me. They repeatedly prove that they categorically can't be jailed or trusted.

dfee · 4 months ago

> April does not write emails for you unless you specifically ask for it.

> But do you think a 'safe mode' - where April does only non destructive operation like read/summarize/draft/move emails to a folder would help you build trust?

> It's in our pipeline

Wat

SamBam · 4 months ago

> April does not write emails for you unless you specifically ask for it. Users usually dictate what they want to reply.

> Send replies that I dictate (it handles the formatting and tone)

How does it handle the tone without editing your dictation?

monkeydust · 4 months ago

Yes, think this needs to be way up on your priority list.

vedhsaka · 4 months ago

Point taken - Safe mode goes out this week.

rukuu001 · 4 months ago

I am building just such a thing, with an overall limitation that it will only interact with emails that only have our team on them. It’s fun

mashlol · 4 months ago

ankit219 · 4 months ago

I like the idea. I also think you may need a mechanism to detect adverse actions before they are executed. This becomes important because an email cannot be unsent, and if I dont review the text, the 1 in 100 chance of the email sounding weird would freak me out. There is also the basic corner cases against AI prompt injection and all those spam and phishing emails that are rampant and more and more plausible sounding. Wonder if you have ideas around how to deal with those?

nehasuresh1904 · 4 months ago

Absolutely. We will be adding a safe mode where April can perform only read, summarize emails & calendar schedule, create drafts but cannot send or delete emails.

danenania · 4 months ago

Maybe reading out the draft to confirm before sending could be a nice middle ground? Could help with peace of mind about exactly what's being sent, and you could go back and forth on the message if it's not quite right. Once people use it for awhile and trust it more, they could then enable auto-send.

Congrats on the launch btw—cool stuff!

andrewrn · 4 months ago

I think I watched you guys get into the batch via the mcp hackathon yc had. Congratulations and best of luck with the startup.

Yes Yes! The MCP hackathon was our way in. Thank you, really appreciate the support.

yes :) thank you for the support.

Lienetic · 4 months ago

How are you handling the formatting and tone part of the email so that it doesn't sound like AI? I've tried to use AI tools for email multiple times but always end up significantly editing or rewriting the email myself.

Yeah - April learns how you speak/correct your emails - it picks up your writing patterns and keeps evolving. The more you use it, the more it sounds like you rather than generic AI.

Can you explain a bit more about this? Are you building a profile of what I write and who I write it to? Fetching relevant examples and passing that through some (cloud?) LLM when writing the email?

I'm definitely curious on the technicals but there is also a bit of a trust element here - both on trusting that my email (likely some of my most sensitive data) is handled with care and trust that the actual responses are phrased well.

Gerardo1 · 4 months ago

Your privacy policy and security page say you do not use any user data for training, it also says you don't store any user data. How do you square that with this comment?

- https://tryapril.com/security - https://tryapril.com/privacy

iamflimflam1 · 4 months ago

Sounds very cool. Do you have concerns around what’s Google are doing themselves in this space? What will differentiate you from them?

Hope the above doesn’t come across as negative - just interested in how you see this market developing.

(cofounder here) Honestly, we were hoping Gemini would nail this so we wouldn't have to build it ourselves, but here we are. The main difference is we're not bounded by Google's ecosystem - we're starting with Gmail but already working on Outlook and other integrations. Also, the goal is to build an executive assistant, not just a voice client for email and calendar.

Google native AI integration to Gmail and calendar frequently disappoints be it on desktop or phone (Pixel), it's like Apple and Siri. Should be better given resources but way of base when compared to our expectations.

rockwotj · 4 months ago

Shortwave has had all this and more for over a year and still nothing in Gmail.

peterkelly · 4 months ago

If there's one thing I definitely don't want AI in the middle of, it's communication with other people. The potential for misunderstandings due to hallucination in summaries, both on my end and the recipient's, scares me. There were some pretty bad examples with Apple News.

Accuracy matters, especially when communicating with customers or between managers/employees, and I can imagine many kinds of scenarios where this goes wrong.

TheTaytay · 4 months ago

This looks cool. Any chance you could wrap my Claude Code sessions as well? That's the thing I really want to be voice-driven for my commute. (serious question :) )

That would be supercool - but not the focus point right now. Though I totally see myself using it.

dcreater · 4 months ago

[flagged]

I find my conversations with Claude code to be much higher level than the actual code being written, so it feels more like “I would like my assistant to be able to manipulate text files of all sorts and use scripts to do it”

dang · 4 months ago

No personal attacks, please.

Nash0x7e2 · 4 months ago

Looks awesome! I downloaded the app and was able to get it connected to my accounts, and it is working.

However, I did notice that connect took around a minute to a minute and a half before the agent was in the call and able to speak. Is this a byproduct of the underlying calling service you're using or the traffic?

Regardless, awesome app, curious to see how it continues to improve!

Sorry for the bad experience. It is because of the sudden traffic. Looking at it.