Apollo Sequences and Emails

These endpoints run outreach through your workspace’s Apollo account. You can create a sequence, enroll contacts in it, turn it on and off, and send one email to a contact now or at a set time. Apollo does the sending, from a mailbox of your Apollo team, and tracks opens and replies. Pathbound records each enrollment and each send on the contact’s timeline.

Use them when a script or an AI agent should start outreach from what Pathbound knows about a contact. Every enrollment and every send starts from a Pathbound contact ID.

Before the first call, connect Apollo under Integrations with a connection that includes the sequence permissions, have a workspace admin turn on Sequences or Single email under MCP Tools → Apollo, and use an API key that has the actions:write scope. The MCP server’s apollo_* tools call these endpoints (tools reference), except apollo_add_segment_to_sequence, which calls the segment endpoint.

The reads need actions:write too, because they show your team’s mailboxes, sequences and outreach to each contact. actions:write is opt-in: a key has it only when it was selected at creation.

The connection must include Apollo’s sequence and email permissions. A connection made before September 2026 does not, and is answered 412 needs_reconsent with the missing permissions in details.missing_scopes. A workspace admin reconnects Apollo under Integrations → Apollo.

Apollo answers some of these calls only on a paid Apollo plan. When it refuses for that reason the answer is 412 plan_required.

Two switches under MCP Tools → Apollo decide what may be done. Both are off until a workspace admin turns them on.

Where a switch applies, the API reads it on every call and for every caller. A REST API key is held to it exactly as an MCP connection is, and a call with the switch off is answered 412 tool_disabled. The MCP server also reads the switches to decide which tools it lists.

Listing and canceling single emails are behind no switch in the API, so you can still review and cancel what is queued after Single email is turned off. Over MCP those two tools are listed only while the switch is on.

Every enrollment and every single email names the mailbox it goes out from, in sender_account_id. There is no default.

The mailbox must be one that GET /v1/integrations/apollo/senders returns: active in your Apollo team and, when a workspace admin has set Allowed sender mailboxes under Integrations → Apollo, on that list. With no list set, every active mailbox of the Apollo team may be used.

The mailbox is checked against Apollo again on every write, and once more when a scheduled email is due. A mailbox that is not allowed is refused with 403 sender_not_allowed, and one that is inactive in Apollo with 400 sender_inactive. Another mailbox is never used in its place.

Every POST on this page requires an Idempotency-Key header. Without it the call is refused with 400 IDEMPOTENCY_KEY_REQUIRED, before the body is checked.

Within 24 hours, the same key on the same endpoint does the action once:

• While the first call is still running, a second is answered 409 ACTION_IN_PROGRESS.
• After the first call succeeded, a second is answered 200 with replayed: true, the action_id and a summary of the first result. On an enrollment or a stop the summary holds counts (enrolled_count, skipped_count, updated_count), not the per-contact lists. Nothing is done again.
• After the first call failed, a second runs.

The key alone identifies the action: a different body under a used key is not run. Activate and pause are separate endpoints, so a key used to activate does not block a pause. To activate the same sequence a second time, after a pause, use a new key.

Send an Email keeps its own record: the same key within 24 hours returns the email that the first call created, in whatever state it is now, with replayed: true.

If your client times out, call again with the same key. See also Idempotency.

These endpoints call Apollo while you wait, and Pathbound paces its calls to Apollo. A call that Apollo rate-limits is retried for up to 45 seconds before it is answered 429 rate_limited.

GET /v1/integrations/apollo/senders

Required scope: actions:write

Returns the mailboxes an enrollment or a single email may name. Call it before you enroll or send, and take sender_account_id from it.

curl https://api.pathbound.ai/v1/integrations/apollo/senders \
  -H "Authorization: Bearer $PATHBOUND_API_KEY"

{
  "status": "success",
  "senders": [
    {
      "sender_account_id": "66c8d9e0f1a2b3c4d5e6f701",
      "email": "[email protected]",
      "user_id": "66b7c8d9e0f1a2b3c4d5e6f7",
      "is_default": true,
      "active": true,
      "provider": "Gmail",
      "daily_limit": 50
    }
  ],
  "note": "Ask the user which mailbox to send from and confirm it by email address before enrolling or sending. There is no default."
}

An empty senders means no mailbox may be used: link an active mailbox in Apollo, or have an admin widen Allowed sender mailboxes. The list is read from Apollo and kept for up to a minute.

GET /v1/integrations/apollo/sequences

Required scope: actions:write

Returns the sequences in your Apollo team, including inactive ones created through Create a Sequence.

{
  "status": "success",
  "sequences": [
    {
      "sequence_id": "66f1a2b3c4d5e6f701234567",
      "name": "Q4 renewals",
      "active": false,
      "archived": false,
      "num_steps": 3,
      "schedule_id": "66e0f1a2b3c4d5e6f7012345",
      "is_owner": true,
      "last_used_at": "2026-10-06T14:02:11.000Z",
      "stats": {
        "scheduled": 0,
        "delivered": 42,
        "opened": 30,
        "clicked": 4,
        "replied": 6,
        "bounced": 1
      }
    }
  ],
  "page": 1,
  "per_page": 50,
  "total": 12,
  "total_pages": 1
}

Archived sequences are taken out of each page after Apollo returns it, so a page can hold fewer than per_page sequences.

GET /v1/integrations/apollo/sequence-options

Required scope: actions:write

Returns the two things a sequence can be pointed at: the team’s sending schedules, and the rulesets already applied to the team’s sequences. It takes no parameters.

A sending schedule decides the days and hours Apollo may send a sequence’s emails. You can read the schedules and attach one to a sequence. The windows themselves are edited only in Apollo, under Settings → Sequences → Schedules.

A ruleset is a set of shared settings applied to a sequence. Apollo has no way to list or name rulesets, so this endpoint reports the ruleset IDs found on the team’s sequences, with the sequences that use each one.

{
  "status": "success",
  "schedules": [
    {
      "schedule_id": "66e0f1a2b3c4d5e6f7012345",
      "name": "Normal Business Hours",
      "is_default": true,
      "time_zone": "America/Chicago",
      "use_contacts_time_zone": false,
      "skip_holidays": true,
      "windows": {
        "monday": [[8, 17]],
        "tuesday": [[8, 17]],
        "wednesday": [[8, 17]],
        "thursday": [[8, 17]],
        "friday": [[8, 17]]
      },
      "sending_hours": "Mon–Fri 8:00–17:00"
    }
  ],
  "rulesets_in_use": [
    {
      "ruleset_id": "66d9e0f1a2b3c4d5e6f70123",
      "sequence_count": 4,
      "used_by": ["Q4 renewals", "Trial follow-up"]
    }
  ],
  "note": "Sending windows are set in Apollo (Settings → Sequences → Schedules); …"
}

rulesets_in_use is read from the team’s first 100 sequences.

POST /v1/integrations/apollo/sequences

Required scope: actions:write

Required header: Idempotency-Key

Creates a sequence of 1 to 10 email steps in your Apollo team. The sequence is created inactive and nobody is enrolled, so this call sends nothing. Its steps are ready to send: once contacts are enrolled, activating the sequence is all that starts the emails.

{
  "name": "Q4 renewals",
  "steps": [
    {
      "subject": "Your renewal in December",
      "body": "<p>Hi {{first_name}},</p><p>Your plan renews on December 1.</p>",
      "wait_time": 0,
      "wait_mode": "day"
    },
    {
      "body": "<p>Hi {{first_name}}, a quick follow-up on my note below.</p>",
      "wait_time": 3,
      "wait_mode": "day"
    }
  ]
}

Some settings are fixed. Every step is an automatic email with one version of its text. The sequence finishes for a contact who replies or is marked interested, pauses for one who answers with an out-of-office message, and keeps to Apollo’s bounce list.

{
  "status": "success",
  "action_id": "670f3a1b2c3d4e5f60718293",
  "sequence_id": "66f1a2b3c4d5e6f701234567",
  "sequence_name": "Q4 renewals",
  "active": false,
  "num_steps": 2,
  "note": "Created as an inactive draft. …"
}

schedule_id and ruleset_id are returned when the sequence has them. action_id is the ID of Pathbound’s record of the action.

POST /v1/integrations/apollo/sequences/:sequence_id/activate
POST /v1/integrations/apollo/sequences/:sequence_id/pause

Required scope: actions:write

Required header: Idempotency-Key

activate turns the sequence on: Apollo starts sending its steps to every enrolled contact, from the mailbox each was enrolled with, on the sequence’s schedule. pause turns it off: every enrolled contact is paused and nothing more is sent until the sequence is activated again. To stop particular contacts, use Stop Contacts.

Neither takes a body.

{
  "status": "success",
  "action_id": "670f3a1c2c3d4e5f60718294",
  "sequence_id": "66f1a2b3c4d5e6f701234567",
  "sequence_name": "Q4 renewals",
  "active": true,
  "num_steps": 2,
  "scheduled": 18,
  "note": "Sequence is active: Apollo now sends its steps to enrolled contacts on the sequence schedule. …"
}

active is the state Apollo reports after the call, not the one you asked for. scheduled is the sequence’s scheduled count, as Apollo reports it.

POST /v1/integrations/apollo/sequences/:sequence_id/schedule

Required scope: actions:write

Required header: Idempotency-Key

Points a sequence at one of the team’s sending schedules. This changes the days and hours its emails may go out, for contacts already enrolled too. Only the schedule is changed: the steps, the owner and the on or off state are not touched.

A schedule that is not in your Apollo team is refused with 404 not_found. A schedule with no sending windows is refused with 400 validation, because Apollo does not accept an empty one.

{
  "status": "success",
  "action_id": "670f3a1d2c3d4e5f60718295",
  "sequence_id": "66f1a2b3c4d5e6f701234567",
  "sequence_name": "Q4 renewals",
  "schedule_id": "66e0f1a2b3c4d5e6f7012345",
  "schedule_name": "Normal Business Hours",
  "sending_hours": "Mon–Fri 8:00–17:00",
  "time_zone": "America/Chicago",
  "use_contacts_time_zone": false,
  "active": false,
  "num_steps": 2,
  "note": "Emails for this sequence now go out Mon–Fri 8:00–17:00 (America/Chicago). …"
}

POST /v1/integrations/apollo/sequences/:sequence_id/contacts

Required scope: actions:write

Required header: Idempotency-Key

Enrolls up to 25 contacts in an existing sequence, from the mailbox you name. If the sequence is active, Apollo starts emailing them on the sequence’s schedule. If it is inactive, nothing is sent until it is activated.

curl -X POST https://api.pathbound.ai/v1/integrations/apollo/sequences/66f1a2b3c4d5e6f701234567/contacts \
  -H "Authorization: Bearer $PATHBOUND_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: q4-renewals-batch-1" \
  -d '{
    "contact_ids": [
      "665f1c2ab3d4e5f601234567",
      "665f1c2ab3d4e5f601234568",
      "665f1c2ab3d4e5f601234569"
    ],
    "sender_account_id": "66c8d9e0f1a2b3c4d5e6f701",
    "tags": ["campaign:q4-renewals"]
  }'

Each contact is matched to a contact in your Apollo team by email address, or created there. That costs no Apollo credits.

Apollo decides whom it accepts. It refuses a contact who is already in another sequence, whose email is unverified, who is at a do-not-contact stage, and so on. Apollo has options that override these refusals, and Pathbound never sends them. A refused contact comes back in skipped with Apollo’s reason.

{
  "status": "success",
  "action_id": "670f3a1e2c3d4e5f60718296",
  "sequence": { "sequence_id": "66f1a2b3c4d5e6f701234567", "name": "Q4 renewals" },
  "sender_email": "[email protected]",
  "requested": 3,
  "enrolled": 2,
  "enrolled_contact_ids": ["665f1c2ab3d4e5f601234567", "665f1c2ab3d4e5f601234568"],
  "skipped": [
    { "contact_id": "665f1c2ab3d4e5f601234569", "reason": "no_email" }
  ],
  "tags_applied": ["campaign:q4-renewals"]
}

start_at is echoed when you sent one. A call in which every contact is skipped is still a 200, with enrolled: 0.

A workspace may enroll a set number of contacts a day through these endpoints and the MCP tools together, counted in UTC. Skipped contacts do not count. A call that would pass the cap is refused with 429 budget_exceeded.

To enroll every member of a saved segment as a background job, use POST /v1/segments/:ref/actions.

POST /v1/integrations/apollo/sequences/:sequence_id/contacts/stop

Required scope: actions:write

Required header: Idempotency-Key

Stops up to 25 contacts in a sequence so that no further step is sent to them, or removes them from it.

{
  "status": "success",
  "action_id": "670f3a1f2c3d4e5f60718297",
  "sequence_id": "66f1a2b3c4d5e6f701234567",
  "mode": "stop",
  "requested": 2,
  "updated": 1,
  "updated_contact_ids": ["665f1c2ab3d4e5f601234567"],
  "skipped": [
    { "contact_id": "665f1c2ab3d4e5f601234569", "reason": "not_enrolled" }
  ]
}

updated counts the contacts Apollo was asked to stop or remove. A contact is skipped with not_found_in_pathbound, or with not_enrolled when Pathbound has never enrolled or emailed it through Apollo. Pathbound does not check with Apollo that each of the others was in this sequence.

GET /v1/integrations/apollo/contacts/:contact_id/sequence-activity

Required scope: actions:write

Returns what happened to one contact in Apollo sequences: Pathbound’s own enrollment records, and Apollo’s activity feed for the contact.

This read counts toward your usage the way reading the contact’s timeline does. See Usage and metering.

{
  "status": "success",
  "contact_id": "665f1c2ab3d4e5f601234567",
  "apollo_contact_id": "66a6b7c8d9e0f1a2b3c4d5e6",
  "enrollments": [
    {
      "sequence_id": "66f1a2b3c4d5e6f701234567",
      "sequence_name": "Q4 renewals",
      "status": "replied",
      "sender_email": "[email protected]",
      "enrolled_at": "2026-10-06T14:02:11.000Z",
      "last_event_at": "2026-10-08T09:41:27.000Z"
    }
  ],
  "events": [
    {
      "type": "replied",
      "occurred_at": "2026-10-08T09:41:27.000Z",
      "sequence_id": "66f1a2b3c4d5e6f701234567",
      "sequence_name": "Q4 renewals",
      "step_position": 1
    },
    {
      "type": "enrolled",
      "occurred_at": "2026-10-06T14:02:11.000Z",
      "sequence_id": "66f1a2b3c4d5e6f701234567",
      "sequence_name": "Q4 renewals"
    }
  ]
}

Opens, clicks and replies to each message are on the contact’s timeline, as events.

POST /v1/integrations/apollo/contacts/:contact_id/send_email

Required scope: actions:write

Required header: Idempotency-Key

Sends one email to a contact through Apollo, from the mailbox you name, now or at send_at. The email goes to the contact’s email address, read from the contact record. The request cannot set it.

curl -X POST https://api.pathbound.ai/v1/integrations/apollo/contacts/665f1c2ab3d4e5f601234567/send_email \
  -H "Authorization: Bearer $PATHBOUND_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: followup-665f1c2a-2026-10-13" \
  -d '{
    "sender_account_id": "66c8d9e0f1a2b3c4d5e6f701",
    "subject": "Following up on Thursday",
    "body": "Hi Ada,\n\nHere are the notes from our call.",
    "body_format": "text"
  }'

The answer is 202 when the email was scheduled and 200 otherwise.

{
  "status": "success",
  "email": {
    "scheduled_email_id": "670f3b2c3d4e5f6071829304",
    "contact_id": "665f1c2ab3d4e5f601234567",
    "sender_account_id": "66c8d9e0f1a2b3c4d5e6f701",
    "subject": "Following up on Thursday",
    "send_at": "2026-10-13T15:04:05.000Z",
    "status": "sent",
    "attempts": 1,
    "apollo_message_id": "670f3b2d9a8b7c6d5e4f3a2b",
    "sent_from": "[email protected]",
    "sent_at": "2026-10-13T15:04:08.000Z",
    "action_id": "670f3b2c3d4e5f6071829303",
    "created_at": "2026-10-13T15:04:05.000Z"
  }
}

A 200 does not mean the email was sent. Read email.status. Once the request has passed its checks, whatever happens to the email is reported on the email, not as an HTTP error.

The body of the email is not returned.

Pathbound holds a scheduled email itself and hands it to Apollo at send_at. At that moment, and for an email sent now, it checks again that:

• the API key that asked is still active and still has actions:write, and its owner is still a verified member of the workspace (principal_revoked otherwise);
• Single email is still on and the Apollo connection still works;
• the contact still exists, and its email address is the one it had when you asked (recipient_changed otherwise);
• the mailbox may still be used.

An email that fails one of these ends failed. It is never sent from another mailbox or to another address.

An email is delayed and tried again when the mailbox has reached its Apollo sending limit (an hour later), when Apollo rate-limits the call, when Apollo fails (15 minutes later), or when the workspace has sent its daily allowance of single emails (at the start of the next day, UTC). After four attempts it ends failed.

An email is handed to Apollo at most once. If Apollo’s answer is lost, the email stays sending while Pathbound asks Apollo for its status, and it ends failed with failure.code unconfirmed if Apollo never confirms it. Such an email may have gone out: look at the message in Apollo before you send it again.

failure.code is one of the error codes below, principal_revoked, recipient_changed, unconfirmed, or Apollo’s own reason when Apollo reports that the send failed.

GET /v1/integrations/apollo/scheduled-emails

Required scope: actions:write

Returns the single emails created through Send an Email, whatever their state, latest send_at first. Emails that were sent at once are listed too.

{
  "status": "success",
  "emails": [
    {
      "scheduled_email_id": "670f3b2c3d4e5f6071829305",
      "contact_id": "665f1c2ab3d4e5f601234567",
      "sender_account_id": "66c8d9e0f1a2b3c4d5e6f701",
      "subject": "Your renewal in December",
      "send_at": "2026-10-20T14:00:00.000Z",
      "status": "scheduled",
      "attempts": 0,
      "sent_from": "[email protected]",
      "action_id": "670f3b2c3d4e5f6071829306",
      "created_at": "2026-10-13T15:10:00.000Z"
    }
  ]
}

Each entry has the fields of email in Send an Email. Before an email is sent, sent_from is the address of the mailbox you chose.

DELETE /v1/integrations/apollo/scheduled-emails/:id

Required scope: actions:write

Cancels an email that is scheduled or delayed. An email in any other state cannot be canceled, and the call is refused with 409 validation and the state in details.status. The Idempotency-Key header is optional here.

{
  "status": "success",
  "email": {
    "scheduled_email_id": "670f3b2c3d4e5f6071829305",
    "contact_id": "665f1c2ab3d4e5f601234567",
    "sender_account_id": "66c8d9e0f1a2b3c4d5e6f701",
    "subject": "Your renewal in December",
    "send_at": "2026-10-20T14:00:00.000Z",
    "status": "canceled",
    "attempts": 0,
    "sent_from": "[email protected]",
    "action_id": "670f3b2c3d4e5f6071829306",
    "created_at": "2026-10-13T15:10:00.000Z"
  }
}

An email that was still scheduled created nothing in Apollo, so there is nothing to remove there. A delayed email has been through a send attempt: the contact was matched or created in Apollo and a draft message was written there before the send was refused, and canceling does not remove them. Delete the draft in Apollo if you do not want it kept.

Each enrollment, each stop and each email that was sent is written to the contact’s timeline as a pathbound_action event. Its data.action_type is apollo_add_to_sequence, apollo_stop_in_sequence or apollo_send_email, and data carries the sequence, the subject and the sending address, as they apply.

What recipients then do is read back from Apollo about every 30 minutes and written to the same timeline: apollo_email_sent, apollo_email_opened, apollo_email_clicked, apollo_email_replied, apollo_email_bounced, apollo_email_unsubscribed, apollo_email_spam_blocked, apollo_sequence_finished, apollo_sequence_stopped and apollo_sequence_failed.

An error has the shape { "status": "error", "code": "…", "error": "…" }, with a hint and details where the tables name them. See Errors for the answers every endpoint shares.

The first four 412 answers are checked in the order of the table: connected, accepted, permissions, switch.

GET /v1/integrations/apollo/scheduled-emails and DELETE /v1/integrations/apollo/scheduled-emails/:id do not call Apollo. Of the rows above, only the 400 and the scope 403 apply to them.

Everything Apollo refuses after these checks, such as a contact under Do Not Contact or a mailbox at its limit, is reported in email.status and email.failure, not as an HTTP error.