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API (Beta)

OutboundSync API

Start with Try the API, create a key, then use OutboundSync API v1 for connections, sources, readiness, and webhooks.

When to use this guide: You want a programmatic way to verify an OutboundSync API key, inspect which CRM connections it can access, check whether your sync pipeline is ready, or help an AI coding assistant build against OutboundSync.

The OutboundSync API is the developer surface for OutboundSync itself. It is separate from the Smartlead, Instantly, EmailBison, HeyReach, and other external API keys you save so OutboundSync can read from those tools.

The API is in Beta. Introspection endpoints (/me, /account/status, /connections, /sources, /contacts/outreach) are stable and read-only. Mutations that require the write scope include sync retry, destination replay, blocklist pause/resync, and the Webhooks surface. We may add fields and endpoints as the surface grows.

Start here

Section titled “Start here”

Pick the path that matches where you are:

Try the APISend live requests from these docs. Start with a keyless health check, then paste a key for your account.
Creating API keysCreate, store, rotate, revoke, and scope OutboundSync API keys from the admin app.
Platform health endpointsPublic /health endpoints to monitor OutboundSync availability — no API key required.
API v1 referenceFull contract for every account endpoint, vocabulary, status codes, and the security model.
Check prior outreach for a contactCall contacts/outreach from an agent, low-code HTTP module, or enrichment column.
OutboundSync webhooksRegister Sync Monitoring webhooks, verify signatures, and understand delivery retries.
OutboundSync MCPConnect Cursor, Claude Code, or Codex to hosted MCP tools over API v1.
OutboundSync Agent SkillsInstall public Agent Skills for launch readiness, CRM analysis, copy, and deliverability.
Errors and rate limitsHandle invalid keys, disabled API access, rate limits, and retry behavior.

Machine-readable contract (OpenAPI 3.1):

Base URL and authentication

Section titled “Base URL and authentication”

Account endpoints live under /api/v1 and use Bearer authentication:

https://app.outboundsync.com/api/v1
Authorization: Bearer osapi_<your-secret>

Platform health endpoints (/health/live, /health/ready) and OpenAPI discovery do not require a key. See Platform health endpoints.

What you can call

Section titled “What you can call”

The public API separates sources → destinations from webhooks: a source is an inbound URL you paste into a sequencer (UI: Sources), a destination is either a Forwarding destination URL or a Reply relay that CC’s a sales rep on prospect replies, and webhooks are OutboundSync-emitted Sync Monitoring events delivered to endpoints you register (UI: Webhooks).

Endpoint Auth Purpose
GET /health/live None Is the platform process up?
GET /health/ready None Can it receive and sync events right now?
GET /api/v1/openapi.json None OpenAPI 3.1 document (JSON).
GET /api/v1/openapi.yaml None OpenAPI 3.1 document (YAML).
GET /api/v1/me Bearer Validate the key, list accessible CRM connections, discover related endpoints via links.
GET /api/v1/account/status Bearer Pipeline readiness with blockers[] and warnings[].
GET /api/v1/account/metrics Bearer Request, sync, and destination-delivery counts for a from/to date range (max 31 days).
GET /api/v1/connections Bearer CRM connections with OAuth status and plan capabilities.
GET /api/v1/sources Bearer Inbound paste URLs, platform config, and destination bindings.
GET /api/v1/contacts/outreach Bearer Prior-outreach summary for a contact email and/or social profile URL.
GET /api/v1/requests Bearer Inbound receipts for a from/to date range (max 31 days).
GET /api/v1/syncs Bearer CRM sync attempts for a from/to date range (max 31 days).
POST /api/v1/syncs/:id/retry Bearer (write) Enqueue a HubSpot/Salesforce Error sync retry.
GET /api/v1/destinations Bearer Forwarding destination catalog (list + get).
GET /api/v1/destinations/:id/deliveries Bearer Outbound delivery attempts for one forwarding destination.
GET /api/v1/deliveries Bearer Account-wide destination delivery export for a from/to date range.
POST /api/v1/destinations/:id/deliveries/:deliveryId/replay Bearer (write) Enqueue a replay of one destination delivery.
GET /api/v1/destinations/reply-relays Bearer Reply relay catalog for accessible connections.
GET /api/v1/blocklists Bearer CRM→SEP blocklist syncs (named list).
POST /api/v1/blocklists/:id/pause Bearer (write) Pause fetch and SEP push.
POST /api/v1/blocklists/:id/resync Bearer (write) Queue a full CRM reload (not an incremental resume).
/api/v1/webhooks Bearer Register and manage Webhooks (Sync Monitoring).
/api/v1/events Bearer Queryable platform event log and delivery history.

Full request and response shapes live in the API v1 reference. Use Try the API for health, account, blocklist, and webhook endpoints from the browser; fetch the OpenAPI URLs directly for discovery (they are not in the console menu). How-to for Sync Monitoring: OutboundSync webhooks.

Authentication flow

Section titled “Authentication flow”
Sequence diagram showing a client calling GET /api/v1/me with a Bearer API key, OutboundSync applying an IP rate limit, validating the key hash, resolving API-enabled CRM connections, and returning a MeResponse.
How OutboundSync validates an API key before returning account and connection details.

Quick test

Section titled “Quick test”

Prefer the in-docs console when you can — Try the API needs no tooling. Use GET /api/v1/me as the first authenticated request. A successful response proves the key is valid and shows whether it is account-wide or scoped to one CRM connection.

curl 'https://app.outboundsync.com/api/v1/me' \
  -X GET \
  -H 'Authorization: Bearer osapi_<your-secret>'

Ask an AI coding assistant

Section titled “Ask an AI coding assistant”

For how MCP, the API, Skills, and Sync Monitoring Webhooks fit one agentic loop, start at AI and Agents. Prefer connecting OutboundSync MCP when your harness supports Streamable HTTP — it wraps the same API v1 tools with your Bearer key. Without MCP, use the public Agent Skills over REST — start with Install skills instead of pasting a long rule:

Terminal window
npx skills add outboundsync/skills --skill api -g
npx skills add outboundsync/skills --skill preflight -g
npx skills add outboundsync/skills --skill sync-monitoring -g

See API, Preflight, and Sync monitoring.

For a quick key check only, paste this into Cursor, Claude Code, Codex, or another coding assistant after you create an API key:

Verify my OutboundSync API key against GET https://app.outboundsync.com/api/v1/me.
Docs: https://outboundsync.com/docs/api/v1/
OpenAPI: https://app.outboundsync.com/api/v1/openapi.json
Use Bearer authentication. Parse the connections array and tell me which CRM connections this key can access.

OutboundSync docs pages also have mirrored Markdown endpoints under /content/docs/...md/, so coding assistants can retrieve the same reference content in a machine-readable form.