API & Integrations

Why an API Matters for Cold Email and LinkedIn Outreach

If you run cold email campaigns, email warmup, LinkedIn outreach, or multichannel sequences in WarmySender, sooner or later you'll want to drive the platform from the rest of your stack. The REST API exists for exactly that — pushing prospects in from your CRM, exporting reply events to a data warehouse, building an opt-out webhook that respects DNCs in real time, or wiring a Slack alert the moment a positive reply lands. Every action a user can take in the app is exposed as an API endpoint.

The integrations layer sits one level above the API: native, no-code connectors that handle authentication, field mapping, and event delivery for the CRMs and automation tools most outbound teams already run. You should never have to write glue code for a Salesforce contact sync or a Zapier "new reply" trigger — those are first-class integrations.

REST API: Programmatic Control Over Every Object

The WarmySender REST API uses standard HTTP verbs, JSON request/response bodies, and bearer-token authentication. Every endpoint returns predictable status codes and uses cursor-based pagination on list endpoints so you can stream large result sets without missing rows. Rate limits are enforced per workspace and scale with your plan; Enterprise customers get the highest ceilings.

Common API workflows include:

• Prospect ingestion — POST contacts into a campaign from your CRM, lead-list provider, or in-house enrichment pipeline. Include custom fields and they show up as merge variables in your sequence templates.
• Event export — pull opens, clicks, replies, bounces, unsubscribes, and linkedin_accepted events for analytics or RevOps reporting. Replies and unsubscribes are also pushable via webhook for real-time downstream syncing.
• Mailbox + LinkedIn account management — list connected mailboxes, check warmup status, pause and resume campaigns, and inspect LinkedIn account health programmatically.
• Suppression list sync — keep your unsubscribe and DNC lists in sync across tools so a contact who opts out anywhere is suppressed everywhere.

Webhooks: Real-Time Event Delivery

Polling the API on a schedule wastes effort and adds latency. Webhooks push events to your endpoint within seconds of them happening on our side. Configure one webhook URL per event type or a single catch-all endpoint, sign payloads with HMAC, and we'll retry with exponential backoff if your receiver is briefly down. Most teams wire reply events into a Slack channel or a CRM update so reps see hot leads in the same surface they already work from.

Native Integrations: CRMs and Automation Platforms

For teams that don't want to write code, WarmySender ships native, OAuth-backed connectors:

• Salesforce — bidirectional contact and lead sync, plus reply events written back as Salesforce Activities so AEs see the touch history inside their primary workspace.
• HubSpot — contact import, deal-stage triggers to start sequences automatically, and reply events written as HubSpot Engagements.
• Pipedrive — pull contacts from a Pipedrive list view, map deal owner to mailbox, and push reply notifications back into the deal timeline.
• Zapier and Make — every WarmySender event is a Zap/Scenario trigger, every WarmySender API mutation is an action. No-code teams can wire WarmySender to anything in seconds.
• Custom integrations — for niche stacks or proprietary CRMs, the API + webhooks give you everything Zapier exposes plus full control.

Security and Compliance

API keys are scoped per workspace and revocable from the dashboard. Every API request is logged in your audit trail with timestamp, IP, and endpoint, and you can rotate or revoke keys without downtime. OAuth-based integrations follow the standard refresh-token flow so you never store user passwords. We honor SOC 2 Type II controls on data access.

Frequently Asked Questions

Is the API rate limited?

Yes — API calls are rate limited per workspace based on your subscription plan. Enterprise plans have the highest ceilings, and burst allowances exist so a one-time bulk import doesn't get throttled. Every response includes X-RateLimit-Remaining headers so your client can back off gracefully.

Can I build custom integrations?

Absolutely. The REST API documentation covers every endpoint with request/response examples, and the webhook spec includes signed payload schemas for every event type. Most custom integrations take an afternoon — pull contacts in, push events out.

Connect WarmySender to the Rest of Your Stack

Whether you live in a CRM, run an in-house data warehouse, or just want a "new reply" Slack ping, WarmySender's API and integrations meet you where you are. Cold email campaigns, email warmup, LinkedIn outreach, and multichannel sequences — all of it is programmable, and all of it integrates cleanly with the tools your team already uses.