Sales sequences, as code.

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What is OpenSequence?

OpenSequence is an open source, self-hosted API that runs multi-step sequences of email, SMS, call tasks and LinkedIn steps from inside your own product: sales prospecting, recruiting, customer onboarding, renewals, partner outreach, or the sending backend for an AI agent. It has the shape of a self-hosted Svix: one Docker image, a Postgres you own, per-project API keys, and signed webhooks back to your app.

You register senders, contacts and sequences (versioned JSON definitions), enroll people, and read what happened. OpenSequence handles everything in between: scheduling in each contact's time zone, sending from each sender's own inbox, throttling, replies, bounces, opt-outs, meetings booked, exits, analytics, and a webhook when something changes.

It is headless. Bring your own UI, your own CRM and your own infrastructure.

Why own your sequencing

• No per-seat pricing. Sequencing tools bill per rep, every month. This is a container and a database you already run.
• Headless by design. Every sequence, enrollment and result is an API call, so it lives inside your CRM instead of next to it.
• The hard parts are done. Idempotent sends, an append-only run ledger, crash-safe workers, reply and bounce detection, time zones and quiet hours, daily caps per sender.
• Your stack. Postgres for state, and the queue you choose (Postgres, Redis or in-memory). Run the API and the workers together or scale them apart.
• Agent-ready. An MCP server ships in the box, so Claude Code, Cursor or any MCP client can build sequences, enroll leads and read results with a scoped key.

Quickstart

Run it locally with mock providers (no mail server, Allo or Attio account needed):

git clone https://github.com/lguerberg/open-sequence && cd open-sequence
docker compose up

That starts Postgres and the service on http://localhost:8080. Create a project and its API key with the development operator token:

curl -X POST http://localhost:8080/v1/admin/projects \
  -H "Authorization: Bearer dev-admin-token" \
  -d '{"slug":"acme","name":"Acme CRM"}'
# -> { "project": "prj_...", "api_key": "sk_live_..." }   (the key is shown once)

Use it from your code

Install the TypeScript SDK from npm. It is typed from the OpenAPI file.

npm install @opensequence/sdk

Create and publish a sequence:

import { OpenSequence } from '@opensequence/sdk';

const oseq = new OpenSequence({ baseUrl: process.env.SEQ_URL!, apiKey: process.env.SEQ_KEY! });

const { sequence, version } = await oseq.sequences.create({
  name: 'UK intro',
  definition: {
    entry: 'hi',
    exit_on: ['reply'],
    nodes: {
      hi: {
        type: 'outreach',
        channel: 'email',
        action: 'send',
        params: { subject: 'Hi {{ contact.first_name }}', body: 'Quick question…' },
      },
    },
  },
});
await oseq.sequences.versions.publish(sequence.id, version.id);

Then, in the same file, enroll someone as one of your reps:

await oseq.senders.upsert('max', { name: 'Max Rivera', email: '[email protected]' });
await oseq.contacts.upsert('dana', { first_name: 'Dana', email: '[email protected]' });
await oseq.sequences.enroll(sequence.id, { contacts: ['dana'], sender: 'max' });

Hear back when something happens, signed with Standard Webhooks:

import express from 'express';
import { OpenSequence, verifyWebhook } from '@opensequence/sdk';

const oseq = new OpenSequence({ baseUrl: process.env.SEQ_URL!, apiKey: process.env.SEQ_KEY! });
const { secret } = await oseq.webhooks.create({
  url: 'https://crm.acme.com/hooks/seq',
  event_types: ['enrollment.exited'],
});

const app = express();
app.post('/hooks/seq', express.raw({ type: '*/*' }), (req, res) => {
  const event = verifyWebhook({ secret, headers: req.headers, body: req.body });
  console.log(event.type, event.data.exit_reason); // enrollment.exited reply
  res.sendStatus(204);
});
app.listen(3000);

Prefer plain HTTP? Every call above is one request; see the API reference.

Let your agent drive

Run the MCP server (packages/mcp) next to the service and connect any MCP client with a project key:

claude mcp add --transport http opensequence https://mcp.your-domain.com/mcp \
  --header "Authorization: Bearer sk_live_..."

The agent gets tools to validate sequence definitions, check sender readiness, preview and enroll contacts, follow a contact's journey, work tasks and read analytics. A key scoped to enroll cannot touch senders or settings, and the engine refuses double enrollment for agents too.

This is the beginning of the README. Read the rest at the original. Read the full README ↗