Primitive Threads API
Conversation threads spanning received and sent emails
OpenAPI Specification
openapi: 3.1.0
info:
title: Primitive Account Threads API
version: 1.0.0
description: "Primitive is email infrastructure for AI agents. The Primitive API lets you manage domains, emails, webhook endpoints,\nfilters, and account settings programmatically.\n\n## Authentication\n\nMost endpoints require a Bearer token in the `Authorization` header:\n\n```\nAuthorization: Bearer prim_<your_api_key>\nAuthorization: Bearer prim_oat_<oauth_access_token>\n```\n\nAPI keys and OAuth access tokens are org-scoped. Create and manage them in your dashboard\nunder Settings > API Keys. CLI login plus CLI/agent signup endpoints\nexplicitly declare `security: []`; they do not require an API key because\nthey are used to create OAuth CLI sessions.\n\n## Rate Limiting\n\nThe API enforces a sliding window rate limit of **120 requests per\n60 seconds** per organization. When exceeded, the API returns `429`\nwith a `Retry-After` header indicating how many seconds to wait.\n\n## Pagination\n\nList endpoints use cursor-based pagination. Responses include a\n`meta` object with `total`, `limit`, and `cursor` fields. Pass the\n`cursor` value as a query parameter to fetch the next page. When\n`cursor` is `null`, there are no more results.\n\n## Response Format\n\nAll responses use a consistent envelope:\n\n```json\n{\n \"success\": true,\n \"data\": { ... },\n \"meta\": { \"total\": 42, \"limit\": 50, \"cursor\": \"...\" }\n}\n```\n\nErrors follow the same pattern:\n\n```json\n{\n \"success\": false,\n \"error\": { \"code\": \"not_found\", \"message\": \"Email not found\" }\n}\n```\n\n## Webhook signing\n\nOutbound webhook deliveries (configured via the `endpoints` API)\nare signed so receivers can verify they came from Primitive and\nhave not been tampered with in transit. The signing scheme is\ndeliberately simple so it can be reimplemented in any language\nin a few lines. The Node SDK's `verifyWebhookSignature` helper\nis the reference implementation; the wire details below let you\nwrite a verifier in Python, Go, Ruby, etc. without reading our\nsource.\n\n**Header**: `Primitive-Signature: t=<unix-seconds>,v1=<hex>`\n\nA legacy `MyMX-Signature` header is also sent on every delivery\nwith the same value, retained for back-compatibility with\nintegrations written before the rename. New code should read\n`Primitive-Signature`.\n\n**Signed string**: `${timestamp}.${rawBody}` where `timestamp`\nis the Unix-seconds integer from the `t=` parameter and\n`rawBody` is the exact bytes of the HTTP request body BEFORE\nany JSON decoding. Verify against the raw body, not a\nre-serialized parse, or you will silently mismatch on\ninsignificant whitespace.\n\n**Signature**: HMAC-SHA256 of the signed string, hex-encoded\n(lowercase). Use the account's webhook secret as the HMAC key,\nas a UTF-8 byte sequence.\n\n**Secret**: returned by `GET /account/webhook-secret`. The\nstring looks base64-shaped (e.g. `XNHBBW8VqoBjRfNs1tkZj11jTk...`)\nbut is NOT base64; use it AS-IS as a UTF-8 string for the HMAC\nkey. Base64-decoding before HMAC will silently produce\nmismatched signatures.\n\n**Tolerance**: by convention, reject deliveries whose `t=`\ntimestamp is more than 5 minutes off your wall-clock to defend\nagainst replay attacks. The Node SDK's helper enforces this by\ndefault.\n\n**Verification recipe** (any language):\n\n```\n1. Read the raw HTTP body (do not parse).\n2. Read `Primitive-Signature: t=<ts>,v1=<sig>`.\n3. Reject if abs(now - ts) > 300 seconds.\n4. expected = HMAC_SHA256_hex(secret_utf8, f\"{ts}.{rawBody}\")\n5. Constant-time compare expected to sig. Reject if not equal.\n```\n\nFor Node, use `verifyWebhookSignature` from\n`@primitivedotdev/sdk/webhook` (or the higher-level\n`handleWebhook` helper if you want a one-liner). For other\nlanguages, the recipe above is everything you need.\n\nTest deliveries: `POST /endpoints/{id}/test` triggers a fake\ndelivery to your endpoint URL, signed with your real account\nsecret, so you can confirm verification end-to-end without\nneeding real inbound mail. The test response carries the exact\n`signature` header value sent on the wire so you can compare\nstrings directly.\n\n\n## Errors\n\nEvery error response is the same JSON envelope (`{ \"success\": false, \"error\": { \"code\", \"message\" } }`), served as `application/json` with HTTP status codes, following the RFC 7807 problem-details shape. The `error.code` is a stable machine-readable string and `error.message` is human-readable.\n\n## Authorization and roles\n\nAccess is governed by organization role-based access control. Every organization member holds one of three roles — `owner`, `admin`, or `member` — and a credential inherits a role. **API keys** always act at `member` level, regardless of the role of the user who created them, so an API key can never perform owner- or admin-only actions. **OAuth access tokens** act with the authorizing user's current organization role, resolved on each request. Every operation in this spec is part of the member-level surface, so any valid credential can call it. Organization administration that is not part of this API — billing and organization settings — requires an `owner` or `admin` and is performed in the dashboard. Fine-grained per-key scopes (e.g. a send-only or read-only key) are on the roadmap; today the role model is the unit of access control.\n\n## Versioning\n\nThe current stable API is **v1**. All endpoints are served under `/v1/` and are covered by a backward-compatibility guarantee: existing fields and status codes will not change without a deprecation notice.\n\nBreaking changes are announced at least 6 months in advance via changelog and email. Deprecated operations and fields are marked `x-deprecated: true` in the spec and carry a plain-English description of the replacement. The `v1` path prefix is guaranteed stable indefinitely; backward-compatible additions (new optional fields, new endpoints) may be made at any time without a version bump."
contact:
name: Primitive
url: https://primitive.dev
license:
name: Proprietary
url: https://primitive.dev/terms
x-stability-level: stable
x-deprecation-policy: 'Breaking changes are announced at least 6 months in advance. Deprecated fields carry x-deprecated: true. The current stable version is v1.'
servers:
- url: https://api.primitive.dev/v1
description: Canonical API host (PRIMITIVE_API_BASE_URL). Carries every public API operation.
tags:
- name: Threads
description: Conversation threads spanning received and sent emails
paths:
/threads/{id}:
parameters:
- name: id
in: path
required: true
schema:
type: string
format: uuid
description: Resource UUID
get:
operationId: getThread
summary: Get a conversation thread by id
description: 'Returns a conversation thread: its metadata plus the inbound
and outbound messages that belong to it, interleaved in time
order (oldest first). A thread spans both received emails and
your sends, so an agent can reconstruct an entire back-and-forth
from one call instead of walking reply headers.
Each message carries a `direction` (`inbound` | `outbound`) and
an `id`; fetch the full message via `/emails/{id}` or
`/sent-emails/{id}` accordingly. Bodies are omitted here to keep
the thread view lightweight.
Discover a thread id from the `thread_id` field on any email or
sent-email (list or detail). The message list is capped; compare
`message_count` against `messages.length` to detect truncation.
'
tags:
- Threads
responses:
'200':
description: Thread detail
content:
application/json:
schema:
allOf:
- type: object
properties:
success:
type: boolean
const: true
required:
- success
- data
- type: object
properties:
data:
type: object
description: 'A conversation thread: its metadata plus the inbound and
outbound messages that belong to it, interleaved oldest-first.
Membership is the stored `thread_id` on each message. Bodies are
omitted here to keep the thread view lightweight; fetch
`/emails/{id}` or `/sent-emails/{id}` for a single message''s
full content.
'
properties:
id:
type: string
format: uuid
subject:
type:
- string
- 'null'
description: Normalized subject of the thread (Re/Fwd prefixes stripped).
root_message_id:
type:
- string
- 'null'
description: Message-ID of the conversation root, when known.
message_count:
type: integer
description: 'Total messages in the thread. `messages` is capped (most
recent first, then re-sorted oldest-first), so
`message_count > messages.length` signals truncation.
'
first_message_at:
type:
- string
- 'null'
format: date-time
last_message_at:
type:
- string
- 'null'
format: date-time
created_at:
type: string
format: date-time
messages:
type: array
items:
type: object
description: One message in a thread (inbound or outbound).
properties:
direction:
type: string
enum:
- inbound
- outbound
description: '`inbound` for a received email (`/emails/{id}`), `outbound`
for a send (`/sent-emails/{id}`). Use it with `id` to fetch
full content from the right endpoint.
'
id:
type: string
format: uuid
message_id:
type:
- string
- 'null'
from:
type:
- string
- 'null'
to:
type:
- string
- 'null'
subject:
type:
- string
- 'null'
status:
type:
- string
- 'null'
description: Lifecycle status (an EmailStatus or SentEmailStatus value, per `direction`).
timestamp:
type:
- string
- 'null'
format: date-time
description: received_at for inbound, created_at for outbound.
required:
- direction
- id
required:
- id
- message_count
- created_at
- messages
headers:
ratelimit-limit:
description: Maximum number of requests allowed in the current window.
schema:
type: integer
minimum: 1
example: 120
ratelimit-remaining:
description: Remaining requests in the current window.
schema:
type: integer
minimum: 0
example: 118
ratelimit-reset:
description: Unix timestamp (seconds) when the current window resets.
schema:
type: integer
example: 1700000060
ratelimit-policy:
description: Rate-limit policy in `limit;w=seconds` format, e.g. `120;w=60`.
schema:
type: string
example: 120;w=60
'400':
$ref: '#/components/responses/ValidationError'
description: Invalid request parameters
'401':
$ref: '#/components/responses/Unauthorized'
description: Invalid or missing API key
'404':
$ref: '#/components/responses/NotFound'
description: Resource not found
security:
- BearerAuth: []
components:
schemas:
GateDenial:
type: object
properties:
name:
type: string
enum:
- send_to_confirmed_domains
- send_to_known_addresses
description: Public recipient-scope gate name that denied the send.
reason:
type: string
enum:
- domain_not_confirmed
- recipient_unauthenticated
- recipient_not_known
description: Stable machine-readable denial reason.
message:
type: string
description: Human-readable explanation of the gate denial.
subject:
type: string
description: Domain or address the gate evaluated.
fix:
$ref: '#/components/schemas/GateFix'
docs_url:
type: string
description: Public docs URL with more context.
required:
- name
- reason
- message
- subject
ErrorResponse:
type: object
properties:
success:
type: boolean
const: false
error:
type: object
properties:
code:
type: string
enum:
- unauthorized
- forbidden
- not_found
- validation_error
- rate_limit_exceeded
- internal_error
- conflict
- mx_conflict
- outbound_disabled
- cannot_send_from_domain
- recipient_not_allowed
- outbound_key_missing
- outbound_unreachable
- outbound_key_invalid
- outbound_capacity_exhausted
- outbound_response_malformed
- outbound_relay_failed
- discard_not_enabled
- inbound_not_repliable
- search_timeout
- authorization_pending
- slow_down
- access_denied
- expired_token
- invalid_device_code
- invalid_signup_code
- invalid_signup_token
- invalid_verification_code
- email_delivery_failed
- clerk_signup_failed
- no_orgs_for_user
- org_not_accessible
- feature_disabled
- memory_conflict
- developer_usage_credit_exhausted
- no_payout_address
- ownership_proof_failed
- payment_verification_failed
- payment_declined
- challenge_expired
- settlement_failed
- template_not_installable
- scaffold_only
- invalid_variables
- unknown_secrets
- missing_secrets
- no_inbound_domain
- domain_cannot_send
- address_taken
- route_cap_reached
- name_exhausted
message:
type: string
details:
type: object
description: 'Optional structured data that callers can inspect to recover
from the error. The fields present depend on `code`. Additional
keys may be added over time without a major-version bump.
'
additionalProperties: true
properties:
mx_conflict:
type: object
description: Present when `code == mx_conflict`.
required:
- provider_name
- suggested_subdomain
properties:
provider_name:
type: string
description: Human-readable name of the detected mailbox provider (e.g. "Google Workspace").
suggested_subdomain:
type: string
description: Subdomain to try instead (e.g. "mail" for `mail.example.com`).
required_entitlements:
type: array
items:
type: string
description: Entitlements that would allow a denied send when no recipient-scope gate was granted.
sent_email_id:
type: string
description: ID of the persisted sent-email attempt associated with the error.
content_hash:
type: string
description: Content hash of the original request on idempotency cache-hit errors.
client_idempotency_key:
type: string
description: Effective idempotency key associated with the original request.
gates:
type: array
items:
$ref: '#/components/schemas/GateDenial'
description: Structured per-gate denial detail for recipient-scope send-mail failures.
request_id:
type: string
description: Server-issued request identifier for support and tracing.
required:
- code
- message
required:
- success
- error
GateFix:
type: object
properties:
action:
type: string
enum:
- confirm_domain
- sender_must_fix_authentication
- wait_for_inbound
description: Suggested next action for the caller.
subject:
type: string
description: Entity the action applies to.
required:
- action
- subject
responses:
Unauthorized:
description: Invalid or missing API key
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
success: false
error:
code: unauthorized
message: Invalid or missing API key
NotFound:
description: Resource not found
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
success: false
error:
code: not_found
message: Resource not found
ValidationError:
description: Invalid request parameters
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
success: false
error:
code: validation_error
message: Invalid domain format
securitySchemes:
BearerAuth:
type: http
scheme: bearer
description: 'API key with `prim_` prefix or OAuth access token with `prim_oat_` prefix: `Authorization: Bearer <token>`. Access is governed by the caller''s organization role (`owner`, `admin`, or `member`): API keys always act at `member` level regardless of who created them, and OAuth access tokens act with the authorizing user''s current organization role, resolved per request. Every operation in this spec is available to organization members; billing and organization administration are owner/admin actions performed in the dashboard and are not part of this API.'
DownloadToken:
type: apiKey
in: query
name: token
description: Signed download token provided in webhook payloads