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Automate cold email outreach with APIs and webhooks
Run high-volume campaigns with full control over logic, timing, and replies.
Start sends, pause campaigns, and trigger follow-ups via API.
Set conditional logic based on replies, bounces, or lead status changes.
Run automated workflows across multiple inboxes and accounts.
Let webhooks sync real-time updates across your CRM or reporting tools.
Multiple admin API keys one per integration or team member
Up to 25 named API keys. Manage each independently.
Name each key by workflow: "Zapier Integration", "Clay Sync", "Internal Scripts"
Rename, reset, or revoke any key without affecting others
All keys share your existing rate limit
Find it under Settings → API Key Management
Real-time webhooks for smarter sales workflows
Stay in Sync With Real-Time Webhooks.
Instant webhooks on reply, bounce, or unsubscribe. Route events to Slack, HubSpot, or any endpoint.
Every lead event syncs in real time. No manual exports.
Connect your tools and workflows so nothing falls through the cracks.
Replace manual status checks with automated, real-time updates.
Connect to any CRM or app in your stack
Sync leads in real-time via webhooks and the cold email API.
Native integrations with HubSpot, Salesforce, Pipedrive, Zoho, and more.
Connect to 6,000+ apps via Zapier, Make, or N8N.
Trigger workflows the instant a prospect replies, bounces, or books a call.
Keep every team and client dashboard aligned with one always-up-to-date data stream.
Transactional email APIs like SendGrid or Mailgun are built for one-to-one triggered sends, not multi-touch cold outreach at scale. They have no inbox rotation, warmup, or reply detection, making volume sending a deliverability risk. Smartlead's cold email API includes all of that built-in, so you can automate outbound without building the infrastructure from scratch.
Let’s build your intelligent enterprise outreach engine
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What our customers say
Founder, StackOptimise
Smartlead's combination of automation, unlimited inboxes, and easy campaign management has completely transformed how we run cold email campaigns.
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Founder, Cold Email Hackers
We have about 15 companies and we use Smartlead for all of them.
Founder, DutchSave Media
One of the things I love about using Smartlead is the deliverability feature. If they landed in the bounce or spam folders, we could resolve this quickly.
Co-Founder, Growth Today
I want to continue to use Smartlead to make operations more seamless - the plan is to bring more clients here and build more SOPs.
Founder, FueltoFly
Smartlead listens to the agencies and customers and builds according to what people want, that has really made things easier for us.
Founder, OutboundSync
We build an infrastructure product, and OutboundSync communicates with Smartlead itself. I love the webhook and API. They're really well done and keep getting better.
Founder, Axoleads
With SmartDelivery, you can put all of that in the hands of the tool. It ensures your emails land in inboxes, and by running a simple test, you can see if you're hitting the mark.
Founder, Claygen
Deliverability is the cornerstone of cold email outreach. You could have the best email copy in the world, but if no one is seeing it, it's useless. I really love the feature where you can actually give client accesses to your clients.
Co-Founder, Cymate
I do not want to switch to another software. Pick a solution you trust, stick with it, and keep refining your copy.
CMO, Avalanche Capital
Managing large volumes of emails through multiple inboxes used to be a logistical nightmare. With Smartlead, the process is seamless. We book thousands of discovery calls through cold emails. These campaigns are generating leads at a scale we never thought possible.
Founder, Growth Engine X
We came for the unlimited inboxes, and we stayed for the API. 1.5M cold emails/month, 7,767+ inboxes managed.
Head of Community & Ecosystem, TxtCart
You cannot replace having 10,000 touches with potential clients. When you have that much distribution and reach, you really start to see incredible results. The simplicity of Smartlead made all the difference. It doesn't require you to be a technical wizard.
Founder, Hyperke
Smartlead has been a game-changer for us. It increased our appointment volume, improved ease of use, and offered valuable features. 80% increase in appointments/month, peak of 276 appointments in a single month.
Founder, Kinetyca
Smartlead has been our cold email backbone from day one. The platform evolves constantly, keeping pace with how deliverability and personalization need to work today. 21% overall reply rate, $175K in 4 months for multiple B2B clients.
Founder, Reachflow
Smartlead is centered around deliverability and constantly evolving. Their API is not like any other platform. Smartlead covers all our needs. The focus on core features like deliverability and API integration is unmatched.
CEO, Halfwarm
Our approach to crafting conversational emails led to reply rates that many of my peers thought were unattainable.
Co-Founder, letstrike
We've grown on zero capital, zero marketing, purely cold emailing - and that's the story we love to tell. The best approach is no approach if you can't handle domain meltdown. The second best is something like Smartlead that's built from the ground up for deliverability at scale.
Founder, Fenixtal
Smartlead's white-labeling and automation let us punch above our weight. The 12M euros sales potential? That's what happens when you combine human creativity with Smartlead's precision.
Co-Founder, Digital Creativs
Nine out of 10. Ninety percent of our clients are on Smartlead unless they come in with an existing setup. That's the default.
Co-Founder, BuildingReach
At the end of the day, you have to take a bet on one tool or another. It was a no-brainer taking that bet on Smartlead. We had to even turn down the volume of our marketing campaigns - Smartlead was capable of driving more volume than our sales team was able to fulfill.
Founder & MD, Prospectiv
Since starting the business in January of this year, we've already generated $200K in sales exclusively from cold email. Smartlead has been central to our operations and has exceeded our expectations.
Founder, Growthlynk
There's so much stuff built on top of it. I would be dead if I had to rebuild it with another tool. I can manage hundreds of senders easily. I can send hundreds of thousands of emails.
Founder, Corebits
The platform's HubSpot integration, real-time Slack updates, and advanced campaign customization have been game changers for our business and our clients'.
Founder, Apex Ascension
From day one, we've never used anything else.
Powerful automated workflows that drive sales.
Frequently asked questions
What is Smartlead’s API used for in cold email automation?
Smartlead’s API lets you control campaign sends, manage inboxes, update lead statuses, and automate follow-ups—all from your internal systems.
Can agencies use Smartlead API to manage multiple client accounts?
Yes. Agencies can use the API to manage campaigns, leads, and inboxes across unlimited accounts from one centralized system.
Is there documentation available for Smartlead’s API and webhooks?
Yes. You can access full Smartlead API documentation and webhook setup guides from the API Docs page.
How do webhooks work in Smartlead?
Smartlead webhooks notify you in real time when key events happen—like a lead replying, bouncing, or unsubscribing—so you can trigger custom actions instantly.
What kind of workflows can be automated using Smartlead API and webhooks?
You can automate cold email sends, lead routing, follow-up triggers, CRM syncing, reporting, and status updates—ideal for large-scale outreach.