API and webhooks

No connector for your app? Plug it in directly.

Mailsoftly gives every account a documented REST API, webhooks in both directions and OAuth 2.1 for apps you build for others. Any application that can send or receive an HTTP request can create contacts, start automations, receive contact data and send campaigns, with no native connector needed.

Start free with Google Start free with Microsoft 365 Get a demo

Free to start with your Google Workspace or Microsoft 365 account · No credit card required

Your app or toolAnything that speaks HTTP

REST API or webhookAPI key or OAuth token

MailsoftlyContacts, lists, automations, campaigns

Connected

47 documented endpoints, webhook triggers and webhook steps, OAuth 2.1 with scoped permissions. Docs at app.mailsoftly.com/developers.

Join thousands of businesses

5.0

TrustRadius

4.8

4.9

5.0

5.0

How it works

Three ways in, one way out

Pick the layer that fits the job. A quick script uses an API key. An automation that should start from another app uses a webhook trigger. Data that should flow out uses a webhook step. An app you ship to other Mailsoftly customers uses OAuth.

REST API with an API keyCreate an API key under Settings and the Advanced group, then call any of the 47 documented endpoints: contacts, lists, tags, custom fields, campaigns, templates, senders, automations, forms, landing pages, segments and suppressions.

Webhooks in both directionsA webhook trigger gives an automation its own URL, so any app that posts to it starts the flow. A Send Webhook step inside an automation posts the contact's data to your endpoint, with headers and body you control.

OAuth 2.1 for apps you buildApps built for other Mailsoftly customers connect through OAuth with PKCE, scoped permissions and a consent screen. Customers see and revoke connected apps in their settings.

API keySettings, Advanced, Create New API Key

Webhook triggerAny app posts to the automation's URL

Send Webhook stepContact data out to your endpoint

Your app is connectedLive

What the API covers

The whole account, not just contacts

The API is the same surface the product runs on, grouped by what you would reach for. Every operation is documented with request and response examples and the OpenAPI spec is downloadable, so your audience and campaigns are fully scriptable.

👤 Audience

Contacts, lists, tags, fields

Create, update, search and read contacts. Manage lists, tags, custom fields and segments. Add global unsubscribes and suppression entries so opt-outs from your own systems are honored everywhere.

ContactsContact listsTagsCustom fieldsSegmentsSuppressions

📧 Sending

Campaigns, templates, senders

Read campaign status, draft and send emails, manage templates, signatures and verified senders, and run SMS campaigns from the same account.

EmailsEmail templatesSendersSignaturesSMS campaigns

⚡ Growth and automation

Forms, landing pages, automations

Read and work with automations, sign-up forms and landing pages, plus account and integration data, so your own product can build on what Mailsoftly already does.

AutomationsFormsLanding pagesAccountIntegrations

Read the API documentation →

What people build

Six things teams wire up with the API and webhooks

Most integrations are small: one trigger, one endpoint, done in an afternoon.

Your own signup formPost to the API when someone subscribes on your product or site, and they are on the list before the page reloads.

CRM or billing system syncNew customers in your CRM, help desk or billing tool become contacts, tagged by plan or stage.

Automation started by your appA webhook trigger URL per automation, so a purchase, a booking or a milestone in your product starts the right sequence.

Data back to your databaseA Send Webhook step posts contact fields to your endpoint the moment an automation reaches it.

Consent kept in syncOpt-outs in your own system become global unsubscribes or suppression entries in Mailsoftly.

An app for your customersAgencies and software vendors connect their product to their customers' Mailsoftly accounts through OAuth, with scoped permissions.

No developer on hand? Zapier connects thousands of apps with no code, and the native integrations cover the most common tools. AI assistants have their own door: the Mailsoftly MCP server.

Set it once

From your app's event to a sent email, no hands

A webhook trigger starts an automation, the automation sends the email and can post data back with a webhook step. Build it once in the automation builder and it runs on every event.

Event in your appPurchase, booking, signup

Webhook triggerAutomation starts

Email sentFrom your Mailsoftly account

Webhook stepData posted back to you

Built to be built on.

The API runs on the same platform as the product, with an API key for your own scripts and OAuth 2.1 for apps you ship to others. Scoped tokens, a consent screen, short-lived access tokens and a Connected apps page keep customers in control. For AI tools, the MCP server exposes the same account in plain language.

documented endpoints

OAuth

2.1 with PKCE and scoped permissions

Free

to start, no credit card

REST APIAPI key or OAuth token

Webhook triggerany app starts an automation

Send Webhook stepdata out to any endpoint

MCP serverfor AI tools

FAQ

The API and webhooks, answered

Does Mailsoftly have an API?

Yes. Mailsoftly has a documented REST API with 47 endpoints covering contacts, lists, tags, custom fields, segments, campaigns, templates, senders, automations, forms, landing pages, SMS and suppressions. The documentation and the OpenAPI spec live at app.mailsoftly.com/developers.

How do I authenticate?

Two ways. For your own scripts and internal tools, create an API key under Settings and the Advanced group and send it in the Authorization header. For an app used by other Mailsoftly customers, use OAuth 2.1: authorization code flow with PKCE, scoped permissions, short-lived access tokens and refresh tokens.

Does Mailsoftly support webhooks?

Yes, in both directions. A webhook trigger gives an automation a URL that any app can post to, which starts the flow for that contact. A Send Webhook step inside an automation posts the contact's data to a URL you choose, with custom headers and body parameters. Simple inbound endpoints for creating contacts, adding tags, adding to lists and adding suppressions are also available for apps that only speak webhooks.

Can I start an automation from my own app?

Yes. Add a webhook trigger to the automation and it gets its own URL. When your app posts to it, the automation runs for that contact: welcome sequence, follow-up, internal alert, whatever you built.

Can I build an app that other Mailsoftly customers connect?

Yes. Mailsoftly is an OAuth 2.1 provider. Your app registers, sends users through Mailsoftly's consent screen, and receives a token scoped to what it asked for: contacts read or write, campaign drafts, sending, suppressions, account. Sending is a separate opt-in on the consent screen, and customers can revoke your app anytime from Connected apps in their settings. Tell us what you are building and we will help you launch it.

Is the API free to use?

Yes. The API, webhooks and OAuth are available on every plan, including the free plan that starts with your Google or Microsoft account and no credit card. Sending volume follows your plan.

Can AI tools use the API?

Yes, through the Mailsoftly MCP server. It exposes contacts, lists and campaigns to any MCP-compatible assistant with OAuth sign-in and the same scoped permissions. See the MCP server page.

What else does Mailsoftly connect to?

Google Workspace, Microsoft 365, HubSpot, WordPress, Shopify, Jotform and Zapier connect natively, with no code. See the full picture on the Mailsoftly integrations page.

Connect your own app today

Start free with Google Start free with Microsoft 365

No credit card required · Cancel anytime · Real humans on support

CREATE

SEND & AUTOMATE

AUDIENCE & LEADS

MEASURE & CONNECT

RESOURCES

USE CASES

TEMPLATES