← Back to all hacks
Level 1 · Foundations

Inbox leads

Your first 100 customers are likely already in your inbox. You've emailed them, they've emailed you. They are past colleagues, beta testers, friends, and people you met once. This playbook shows you how to systematically mine your email history to find your most qualified early leads and turn them into paying customers.

Effort
Low
Cost
Zero
Time to first result
Hours
Best for
Early-stage founders
Save this playbook

Save this strategy and send it to my inbox

Get the full playbook - scripts, tool stack and checklist - delivered as a single email you can act on today.

No spam. One email, and only what is worth reading.

An illustration of a person fishing for glowing fish inside a giant email inbox.
Your inbox is a well-stocked pond of warm leads.

Why this works

Old contacts are not cold leads. You're re-connecting with people who already know you, trust you, and have context for who you are. This starting point of trust means they're far more likely to open your email, hear you out, and give you honest feedback, if not their credit card number. It bypasses the noise and skepticism of pure cold outreach.

This method forces you to be specific and personal. You can't mass-email your way through this. You have to recall your last conversation, reference a shared experience, and tailor your message. This high-touch, 1-to-1 approach has a much higher conversion rate than any scaled-up marketing campaign, which is exactly what you need in the early days to get your first trickle of revenue and feedback.

Three real examples

B2B SaaSReached $30k MRR

Groove gets first customers from email contacts

Before they had a product, the Groove team built a list of hundreds of people from their personal email contacts. They emailed this list asking about their customer support pain points. This outreach didn't just validate their idea- it also produced their first beta users and paying customers, forming the foundation for their growth.

Source: Groove Blog
Automation SaaS100+ interested users in a weekend

Zapier finds early users in forums

Zapier co-founder Wade Foster knew where his target users hung out online- forums. But he also used his email to follow up with every single person who showed interest in his forum posts. He'd send them a personal note, ask for feedback, and manually onboard them. This direct email engagement with slightly-warm leads was critical for getting their first 100 users.

Source: First Round Review
Solo FounderThe first 10 customers

Every Indie Hacker's first step

Countless founders on Indie Hackers report using this exact tactic. They dig through their Gmail, find 50-100 people they've had contact with in the past year, and send a personal note about their new project. It's the standard, go-to move for a technical founder who needs to start marketing but doesn't know where to begin. It's how you get your first conversations and your first believers.

Source: Indie Hackers

Don't forget to search your social media DMs (LinkedIn, Twitter) as well- they are just as valuable as your email inbox.

The step-by-step playbook

  1. 1

    Step 1: Define your Ideal Customer

    Who are you trying to sell to? Be specific. 'Early-stage SaaS founders' is better than 'businesses'. 'Product Managers at series B companies' is better than 'tech workers'. This focus will guide your search.

  2. 2

    Step 2: Brainstorm search keywords

    Think like an archeologist. What words would be in emails to or from your ideal customers? Think about job titles ('designer', 'founder'), old projects, conference names, or phrases like 'intro request' or 'question about'.

  3. 3

    Step 3: Search your inbox

    Go to Gmail or your email client and start searching. Use your keywords. Don't just look at the 'From' field- look for people who were CC'd or mentioned in threads. Search your 'Sent' folder too.

  4. 4

    Step 4: Build a simple prospect list

    Don't overcomplicate it. Open a spreadsheet (or use a tool like Tally.so) with three columns: Name, Email, and Context (e.g., 'Met at SaaS conference 2022', 'Old colleague from Acme Inc.'). Aim for 50-100 names to start.

  5. 5

    Step 5: Prioritize your list

    Go through your list and rank them from 'most likely to be a perfect fit' to 'less likely'. Who are the 10-20 people you'd be most excited to talk to? Start with them. This is your 'A-List'.

  6. 6

    Step 6: Send your outreach email

    Use the script below as a starting point, but personalize every single email. Reference the context you wrote down. Your goal is not to make a sale, but to start a conversation. Keep your ask small and easy.

  7. 7

    Step 7: Track everything

    Add two more columns to your spreadsheet: 'Sent On' and 'Replied?'. Update this diligently. This prevents you from forgetting who you've contacted and when. Forgetting and emailing the same person twice looks sloppy.

  8. 8

    Step 8: Follow up once

    If you don't hear back in 3-5 business days, send a single, polite follow-up. Just reply to your original message and say, 'Hey, just bumping this to the top of your inbox. Let me know if you have any thoughts!' That's it. No more.

The Ask: Your copy-paste email template

Use this template as a starting point. The key is to customize it heavily with your 'Context' note for each person. Keep it short, personal, and make the ask low-effort.

Subject: Quick question / Catching up

Hi {FirstName},

Hope you're doing well. It's been a while! We {context of how you know them, e.g., 'worked together at Acme Inc', 'met at that marketing conference last year'}.

I'm writing because I'm building a new product that helps {target customer} with {the problem you solve}. Given your experience with {their area of expertise}, I immediately thought of you.

Would you be open to taking a look at a 1-minute demo video and letting me know if it's remotely interesting? No pressure at all, but I'd really value your honest feedback.

Best,

{YourName}

Key Questions to Ask Yourself

  • Does this person fit my ideal customer profile today?
  • What was our last interaction? Was it positive?
  • Can I state clearly and concisely how I know them?
  • What is the single smallest, easiest 'ask' I can make?
  • Is my product at a stage where I can proudly show it to them?

The most important questions are about context and the 'ask'. A clear context makes them feel remembered, not spammed. A small ask ('watch a 1-min video') is much easier to say yes to than a big ask ('book a 30-min demo').

Recommended tools

Gmail / Outlook

Free

The search function in your existing email client is the only tool you truly need. Learn the advanced search operators (like 'from:', 'to:', 'subject:') to get specific.

While a spreadsheet works, Tally is a great free tool to build a simple form for yourself. This can make tracking your outreach list feel a bit more organized and intentional.

Jasper.ai

Starts at $39/mo

If you're struggling to phrase your emails, an AI writer like Jasper can help you draft compelling, personalized copy and subject lines that get opened.

VideoAsk (by Typeform)

Starts at $24/mo

Instead of asking them to read a doc, send a link to an interactive VideoAsk. It's more personal and lets them respond with video, audio, or text, reducing friction.

Prices are indicative and change - check the vendor before buying.

Do it faster with AI Prompts

To brainstorm search terms

I'm searching my email inbox for potential customers for my new product. My product is a {one-sentence description of product}. My ideal customers are {ideal customer profile}. Give me a list of 20 keywords and phrases I can use to search my inbox for people who fit this profile. Include job titles, potential topics of conversation, and software they might use.

To draft a personalized email

Act as a founder writing to a past contact. My product is {product name}, it helps {customer} with {problem}. I am writing to {contact name}, who I knew from {context}. Draft a short, friendly, personalized email to re-connect and ask them for feedback on my new project. Make the 'ask' very small and low-friction. Reference our shared context.

To write a follow-up

I emailed a contact {number} days ago about my new project but haven't heard back. Draft a short, polite, non-pushy follow-up email that I can reply with to bump the message in their inbox.

To analyze an email for hooks

Analyze the following email thread and identify 3 'personalization hooks' I can use to start a new conversation with this person about my new product, which is {one-sentence description of product}. Hooks could be personal details, professional interests, or problems they mentioned. Email thread: '''{paste email thread here}'''

Mistakes that kill this play

  • Sending a generic, non-personalized email. This is not a numbers game; it's a relationship game.
  • Forgetting to mention how you know them. This is the most critical piece of information.
  • Making the 'ask' too big. Don't ask for a 30-minute meeting. Ask for a glance at a screenshot or a 1-minute video.
  • Not having a simple system to track who you've emailed. You will forget, and it will get messy.
  • Being afraid to bother people. You're not a stranger selling junk- you're a known contact sharing your life's work. People are generally happy to help.
  • Giving up after one attempt. A single, polite follow-up is professional and often gets a response.
  • Writing long paragraphs about your product. Keep it to one or two sentences. Focus on them, not you.

Your First 7 Days

  • Day 1: Finalize your Ideal Customer Profile. Brainstorm 20+ keywords for your inbox search.
  • Day 2: Spend 90 minutes searching your inbox. Build your raw prospect list of at least 50 people.
  • Day 3: Prioritize your list. Identify your top 10 'A-List' contacts who are the best fit.
  • Day 4: Write and send personalized emails to your 10 A-List contacts. Record the sends in your tracker.
  • Day 5: Process replies. For the rest of your prospect list, rank and identify the next 20 people to contact.
  • Day 6: Send a follow-up email to anyone from Day 4 who hasn't replied.
  • Day 7: Write and send emails to your next batch of 20 contacts. Analyze replies from the first batch- what's working?
Save this playbook

Save this strategy and send it to my inbox

Get the full playbook - scripts, tool stack and checklist - delivered as a single email you can act on today.

No spam. One email, and only what is worth reading.

More Level 1 hacks