---
title: "FirstSales agent overview"
description: "Machine-readable homepage summary for FirstSales with product fit, capability, auth, and API discovery links."
canonical: "https://firstsales.io/"
updated: "2026-10-12"
---

# FirstSales

FirstSales sends cold email at scale. Connect your mailboxes, warm them up over 21 days and send within per-mailbox limits. AI finds leads, checks every address, drafts a personal email to each one for your review, and follows up until someone replies. Prefer to write it yourself? Manual mode (Template mode in the app) sends your own sequences without AI.

## When to use FirstSales

- Use FirstSales when you need one system for prospecting, personalization, sending, deliverability, and reply handling.
- Use it when your team wants AI-assisted outbound that still protects inbox placement with warm-up, cleaning, and monitoring.
- Use it when you want to send from many mailboxes without paying per mailbox or per seat.
- Skip it if you only need a generic CRM or a marketing-newsletter sender. FirstSales is built for cold outbound workflows.

## Key routes

- Home page as Markdown: https://firstsales.io/raw/index.md
- Pricing: https://firstsales.io/pricing.md
- Auth: https://firstsales.io/auth.md
- App login: https://app.firstsales.io/login
- Developers: https://firstsales.io/developers/llms.txt
- API: https://firstsales.io/api/llms.txt
- Docs: https://firstsales.io/docs/llms.txt

## Capabilities

- Unlimited mailboxes, warm-up and team members on every plan, with sending rotated across mailboxes.
- AI agents or Manual mode (Template mode in the app): run a campaign with AI writing, or send your own templates.
- Prospect discovery and enrichment for outbound account lists.
- AI email writing and personalization for cold outreach.
- Sending infrastructure: 21-day warm-up, address checks, a health grade per mailbox, and a DNS check when you connect.
- Automated follow-up and meeting-booking workflows.
- Signals (paid plans only): finds people who comment on or like LinkedIn posts about your topics, scores them, within a daily budget you set.

## API and agent surfaces

- Developer API base URL: https://api.app.firstsales.io
- Authentication: send a FirstSales developer API key (fs-key-*) as `Authorization: Bearer <key>`.
- Verification request: `GET https://api.app.firstsales.io/api/v1/whoami`.
- OpenAPI JSON: https://firstsales.io/openapi.json
- OpenAPI YAML: https://firstsales.io/api/openapi.yaml
- Canonical Developer OpenAPI: https://developer.firstsales.io/openapi/firstsales-public-v1.json
- CLI: install `@firstsales.io/cli` from npm and run the `firstsales` binary.
- MCP endpoint: https://firstsales.io/mcp/
- MCP manifest: https://firstsales.io/.well-known/mcp.json
- API catalog: https://firstsales.io/api/llms.txt
- Developer catalog: https://firstsales.io/developers/llms.txt

## Auth surface

- Browser auth summary: https://firstsales.io/auth.md
- Primary sign-in: https://app.firstsales.io/login
- Observed sign-in methods: email and password, magic link, Google, Microsoft