Flexmail
API integration

Ship Email features without building the integration. Full Flexmail API access via Proxy and 10+ MCP-ready tools for AI agents — extend models and mappings to fit your product.

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Use Cases

Why integrate with Flexmail

Common scenarios for SaaS companies building Flexmail integrations for their customers.

Offer GDPR-compliant transactional email to European customers

SaaS companies serving EU-based users can embed Flexmail as a native email provider, giving customers an EU-hosted, privacy-first option for sending account notifications, invoices, and alerts without additional data processing agreements.

Automate sender and domain onboarding inside your app

Let your users connect their Flexmail account once and provision sending domains, configure return paths, and verify sender identities directly from your UI — removing the need to context-switch into the Flexmail dashboard.

Power invoice and document delivery with proof-of-receipt

Billing, ERP, and accounting platforms can send PDF invoices through their users' Flexmail accounts and surface delivery, open, and bounce timestamps on each record — eliminating 'I never got the bill' disputes.

Build real-time engagement timelines for CRM and ATS workflows

Subscribe to Flexmail webhooks to update contact, candidate, or customer timelines the moment an email is delivered, opened, clicked, or bounced — giving sales, recruiting, and support teams live visibility.

Embed email health dashboards for your users

Pull aggregated Flexmail stats on a schedule to render per-tenant deliverability dashboards inside your product, so customers can monitor sends, opens, and bounces without leaving your app.

What You Can Build

Ship these features with Truto + Flexmail

Concrete product features your team can ship faster by leveraging Truto’s Flexmail integration instead of building from scratch.

Native Flexmail account connection

Let end users connect their Flexmail account through Truto's auth flow, with credentials and token refresh handled for you.

In-app sending domain provisioning

Create, update, and delete sending domains programmatically and poll verification status to guide users through DNS record setup inside your onboarding flow.

Sender identity management UI

Add, list, inspect, and remove verified sender addresses so your users can manage who they send from without ever leaving your product.

Transactional message dispatcher

Trigger 1:1 emails with HTML, text fallbacks, placeholder substitution, metadata, and attachments directly from your application's business logic.

Message audit and delivery lookup

Fetch individual messages or list historical sends to surface delivered, bounced, opened, and clicked states on the related record in your app.

Webhook-driven event sync

Programmatically register, update, and delete Flexmail webhooks so your platform ingests delivery and engagement events in real time instead of polling.

SuperAI

Flexmail AI agent tools

Comprehensive AI agent toolset with fine-grained control. Integrates with MCP clients like Cursor and Claude, or frameworks like LangChain.

list_all_flexmail_api_infos

Retrieve general info about the Flexmail API via the root API info endpoint. Takes no parameters; the upstream documentation defines a 200 OK response but does not document its payload fields.

list_all_flexmail_messages

List messages sent via Flexmail, sorted oldest to most recent, filterable by date range, recipient, sender, subject, tag, metadata and event status. Returns: message_id, created_at, recipient, sent_at, rejected_at, delivered_at, soft_bounced_at, hard_bounced_at, opened_at, clicked_at, _links. Up to 500 per page.

create_a_flexmail_message

Send an email message to 1 recipient via Flexmail. Requires recipient, from, subject, and content (html is mandatory, text optional). Supports placeholder substitution, tags, metadata, open/link tracking, and up to 20 attachments (20MB total incl. base64 overhead). Returns an empty 201 response on success; the URI of the new message is returned in the Location header. Required: recipient, from, subject, content.

get_single_flexmail_message_by_id

Get full details of a single Flexmail message by id, including every event registered for it. Returns: message_id, created_at, recipient, from, reply_to, return_path, subject, html, text, tracking, tag, metadata, attachments, events, _links, personalAccessToken. Required: id.

list_all_flexmail_senders

List the senders registered in your Flexmail account. Returns each sender's id, email_address, verified status, and created_at. Only verified senders can be used to send email messages.

create_a_flexmail_sender

Add a sender identity in Flexmail representing the From email address recipients will see. Returns the id of the newly created sender. Its domain must be a registered sending domain, and the sender only becomes usable after the verification link emailed to that address is confirmed. Required: email_address.

get_single_flexmail_sender_by_id

Get the details of a single Flexmail sender by id, including its verification status. Returns: id, email_address, verified, created_at, _links, personalAccessToken. Required: id.

delete_a_flexmail_sender_by_id

Delete a Flexmail sender by id. Once deleted, it can no longer be used to send email messages. Returns an empty 204 response on success. Required: id.

list_all_flexmail_sending_domains

List the registered sending domains in Flexmail. Returns: id, domain, return_path, authenticated, aligned, ownership_verified, registered_at, _links.

create_a_flexmail_sending_domain

Register a new sending domain in Flexmail for your email messages, optionally configuring a custom return-path for SPF alignment and DMARC pass. Returns: id, personalAccessToken. Required: sending_domain.

get_single_flexmail_sending_domain_by_id

Fetch a Flexmail sending domain by id, including the validation status and DNS records of each authentication mechanism (SPF, DMARC, DKIM, return-path). Returns: id, return_path, _links, personalAccessToken. Required: id.

update_a_flexmail_sending_domain_by_id

Update a registered Flexmail sending domain by id, for example to (re)configure its custom return-path. Returns an empty 204 response on success. Required: id.

delete_a_flexmail_sending_domain_by_id

Delete a registered Flexmail sending domain by id. Returns an empty 204 response on success. Required: id.

list_all_flexmail_stats

Fetch global message statistics for all messages sent through Flexmail, optionally limited to a period via date filters. Returns: sent, delivered, rejected, bounced, soft_bounced, hard_bounced, opens, unique_opens, clicks, unique_clicks, _links. Statistics are updated at regular intervals and are not real-time; use Flexmail's message event webhooks for real-time data.

list_all_flexmail_webhooks

List all webhooks registered in Flexmail. Returns each webhook's id, event_name, target_url, verification_token, enabled, and registered_at. A webhook is disabled after 10 failed retries.

create_a_flexmail_webhook

Create a webhook in Flexmail that subscribes to an event (maximum 10 webhooks per event). Returns: id. Requires event_name and target_url; if identity verification fails, the webhook is not created. Required: event_name, target_url.

update_a_flexmail_webhook_by_id

Change the target URL of a webhook in Flexmail. Returns an empty 204 response on success. Requires id and target_url; identity must be verified again. Required: id, target_url.

delete_a_flexmail_webhook_by_id

Delete a webhook in Flexmail by its id. Returns an empty 204 response on success. Required: id.

Why Truto

Why use Truto’s MCP server for Flexmail

Other MCP servers give you a static tool list for one app. Truto gives you a managed, multi-tenant MCP infrastructure across 800+ integrations.

Auto-generated, always up to date

Tools are dynamically generated from curated documentation — not hand-coded. As integrations evolve, tools stay current without manual maintenance.

Fine-grained access control

Scope each MCP server to read-only, write-only, specific methods, or tagged tool groups. Expose only what your AI agent needs — nothing more.

Multi-tenant by design

Each MCP server is scoped to a single connected account with its own credentials. The URL itself is the auth token — no shared secrets, no credential leaking across tenants.

Works with every MCP client

Standard JSON-RPC 2.0 protocol. Paste the URL into Claude, ChatGPT, Cursor, or any MCP-compatible agent framework — tools are discovered automatically.

Built-in auth, rate limits, and error handling

Tool calls execute through Truto’s proxy layer with automatic OAuth refresh, rate-limit handling, and normalized error responses. No raw API plumbing in your agent.

Expiring and auditable servers

Create time-limited MCP servers for contractors or automated workflows. Optional dual-auth requires both the URL and a Truto API token for high-security environments.

How It Works

From zero to integrated

Go live with Flexmail in under an hour. No boilerplate, no maintenance burden.

Link your customer’s Flexmail account

Use Truto’s frontend SDK to connect your customer’s Flexmail account. We handle all OAuth and API key flows — you don’t need to create the OAuth app.

We handle authentication

Don’t spend time refreshing access tokens or figuring out secure storage. We handle it and inject credentials into every API request.

Call our API, we call Flexmail

Truto’s Proxy API is a 1-to-1 mapping of the Flexmail API. You call us, we call Flexmail, and pass the response back in the same cycle.

Unified response format

Every response follows a single format across all integrations. We translate Flexmail’s pagination into unified cursor-based pagination. Data is always in the result attribute.

FAQs

Common questions about Flexmail on Truto

Authentication, rate limits, data freshness, and everything else you need to know before you integrate.

How is authentication to Flexmail handled?

Truto manages the Flexmail credential exchange and attaches auth to every request. Your end users connect their Flexmail account once through Truto's connection flow — you never store or rotate API keys yourself.

Which Flexmail operations are supported today?

Truto exposes tools for messages (list, create, get), senders (list, create, get, delete), sending domains (list, create, get, update, delete), stats (list), webhooks (list, create, update, delete), and the Flexmail API info endpoint.

Can I send emails with attachments?

Yes. The create message tool supports Flexmail's transactional sending, including HTML, text fallbacks, metadata, placeholder substitution, and attachments (up to Flexmail's limit of 20 files and 20MB combined).

How do I keep delivery and engagement data fresh?

Use the webhook tools to register subscriptions for delivery, bounce, open, and click events so Flexmail pushes updates to your endpoint in real time. For backfills or audits, use the list and get message tools.

Is there a unified email API I can target instead of Flexmail-specific tools?

Not yet — Flexmail is currently exposed through its native tool set. You can build directly against the Flexmail-specific tools listed, and migrate to a unified schema later if one becomes available for this category.

Can my users provision their own sending domains through my app?

Yes. Use the sending domain tools to create a domain, retrieve its current DNS verification state, update it, or delete it — allowing you to walk users through SPF/DKIM/DMARC setup entirely within your product.

From the Blog

Flexmail integration guides

Deep dives, architecture guides, and practical tutorials for building Flexmail integrations.

Flexmail

Get Flexmail integrated into your app

Our team understands what it takes to make a Flexmail integration successful. A short, crisp 30 minute call with folks who understand the problem.