Document inbound forward rules and align the inbound spec with the API by mklocek · Pull Request #59 · mailtrap/mailtrap-openapi

mklocek · 2026-10-05T14:29:37Z

Motivation

The inbound API gained forward rules, per-destination forward outcomes on received messages, a delivery object on sent thread messages, and search on the threads list, none of which the spec documented. Comparing the rest of the inbound spec against the API also turned up descriptions, validation rules and error examples that no longer matched it.

The forward rules code samples call SDK methods that ship in the pending SDK releases, so this should merge once those are out.

Changes

All in specs/inbound.openapi.yml.

Forward rules: new forward-rules tag with list, create, get, update and delete, their schemas and validation error examples, and code samples for cURL, Node.js, PHP, Python, Ruby, .NET and Java
Messages: forwards on each message; last_id described as an opaque cursor, with the 400 for a malformed one
Threads:
- forwards on received messages and delivery (to, status, delivered_at, bounced_at) on sent messages; the flat delivery_status, delivered_at and bounced_at are removed
- search parameter and the 400 responses on list threads
- examples rewritten to match how the API computes the thread aggregates
Folders, inboxes and send endpoints: descriptions, validation rules and error examples corrected to match the API

Summary by CodeRabbit

New Features
- Added inbox forwarding rules, including conditions, destinations, and per-destination outcome details.
- Added case-insensitive thread search with clear input limits and validation.
- Documented custom-domain inbox creation and forwarding recipients for replies and forwards.
Documentation
- Clarified inbox and folder access, limits, and errors; opaque pagination cursors; and how thread messages and delivery details are presented.

coderabbitai · 2026-10-05T14:30:14Z

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📝 Walkthrough

Walkthrough

The OpenAPI specification adds inbox forward-rule endpoints and schemas. It also clarifies folder and inbox access, message and thread pagination and response fields, and recipient and permission rules for sending and replying.

Changes

Inbound API

Layer / File(s)	Summary
Folder and inbox access `specs/inbound.openapi.yml`	Folder and inbox documentation specifies access scope, ordering, deletion effects, inbox limits, custom-domain constraints, and which inbox fields can change.
Forward-rule contracts and operations `specs/inbound.openapi.yml`	New schemas and endpoints document rule conditions and destinations, list and CRUD operations, limits, atomic updates, and validation responses.
Message and thread retrieval `specs/inbound.openapi.yml`	Message and thread documentation covers opaque cursors, thread search, retention, placeholders, aggregates, delivery and forwarding outcomes, and deletion behavior.
Send and reply behavior `specs/inbound.openapi.yml`	Reply, reply-all, and forward documentation describes recipient overrides. Send-message documentation describes recipient options, header restrictions, and permission errors.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~45 minutes

Change: Other

Merge Risk: 🔵 Low · up to df927

This change only updates the API documentation. Two small fixes would make it accurate and usable with generated clients. The 403 response schema for sending is ambiguous, and one thread example points to a message ID that does not appear in the example. The forward-rule code samples also depend on SDK releases that are not yet out.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: documenting inbound forward rules and aligning the inbound API spec with the API.
Description check	✅ Passed	The description explains the motivation and summarizes the changes. It does not include the required “How to test” section or the “Images and GIFs” table, but the core information is complete.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 2

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Inline comments:
Review comments at @specs/inbound.openapi.yml:
- Around line 4483-4485: Replace the `oneOf` response schema with a single
reference to `SendMessageError`; it accepts both documented error shapes and
avoids ambiguous validation for the permission example.
- Line 2335: Update last_message_id in the thread example and the related list
and ThreadSummary examples to use the ID of the most recent available message,
matching the message whose created_at matches last_activity_at.

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specs/inbound.openapi.yml

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- Add the forward rules endpoints (list, create, get, update, delete) - Add the delivery object on sent thread messages and forwards on received messages - Add search and the 400 responses to list threads; describe last_id as an opaque cursor - Correct folder, inbox and send-endpoint descriptions, validation rules and error examples

mklocek · 2026-10-12T09:47:43Z

ping @leonid-shevtsov

IgorDobryn

Approving. The forward-rule operations, the forwards / delivery fields and the thread search parameter look right, and the samples match the released SDK method names. Spectral and Redocly lint are clean.

One should-fix inline: the new PHP samples pass the inbox ID as a string, which throws a TypeError under the SDK's strict types. Each line has a one-click suggestion. The existing inboxes($folderId), messages($inboxId) and threads($inboxId) PHP samples have the same problem (e.g. lines 618, 739, 904, 1011, 1126, 1236), so it's worth casting those too, here or in a follow-up.

IgorDobryn · 2026-10-19T09:40:08Z

-        type: string
-        example: "1700000000000123"
+            $config = new Config($_ENV['MAILTRAP_API_KEY']);
+            $inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];


should-fix: $_ENV values are strings, and the PHP SDK builds the inbound API objects in a file with declare(strict_types=1), so passing the string to forwardRules(int $inboxId) throws a TypeError (reproduced on PHP 8.5). The SDK's own examples/inbound/forward-rules.php casts it:

Suggested change

$inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

$inboxId = (int) $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

IgorDobryn · 2026-10-19T09:40:08Z

+            use Mailtrap\MailtrapInboundClient;
+
+            $config = new Config($_ENV['MAILTRAP_API_KEY']);
+            $inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];


Same TypeError as above, so cast here too:

Suggested change

$inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

$inboxId = (int) $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

IgorDobryn · 2026-10-19T09:40:08Z

+            use Mailtrap\MailtrapInboundClient;
+
+            $config = new Config($_ENV['MAILTRAP_API_KEY']);
+            $inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];


Same TypeError as above, so cast here too:

Suggested change

$inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

$inboxId = (int) $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

IgorDobryn · 2026-10-19T09:40:08Z

+            use Mailtrap\MailtrapInboundClient;
+
+            $config = new Config($_ENV['MAILTRAP_API_KEY']);
+            $inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];


Same TypeError as above, so cast here too:

Suggested change

$inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

$inboxId = (int) $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

IgorDobryn · 2026-10-19T09:40:08Z

+            use Mailtrap\MailtrapInboundClient;
+
+            $config = new Config($_ENV['MAILTRAP_API_KEY']);
+            $inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];


Same TypeError as above, so cast here too:

Suggested change

$inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

$inboxId = (int) $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

mklocek requested review from leonid-shevtsov and piobeny October 5, 2026 14:30

mklocek marked this pull request as ready for review October 5, 2026 14:30

coderabbitai Bot reviewed Oct 5, 2026

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Comment thread specs/inbound.openapi.yml

Comment thread specs/inbound.openapi.yml Outdated

piobeny approved these changes Oct 6, 2026

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mklocek force-pushed the inbound-forward-rules-and-api-sync branch from df927be to 7925868 Compare October 12, 2026 09:41

Add SDK code samples to the inbound forward rules endpoints

f52fabc

mklocek force-pushed the inbound-forward-rules-and-api-sync branch from 7925868 to f52fabc Compare October 12, 2026 09:47

mklocek enabled auto-merge October 12, 2026 10:01

piobeny requested review from IgorDobryn and VladimirTaytor October 16, 2026 11:46

IgorDobryn approved these changes Oct 19, 2026

View reviewed changes

mklocek merged commit 31cc1e4 into main Oct 19, 2026
2 checks passed

mklocek deleted the inbound-forward-rules-and-api-sync branch October 19, 2026 09:40

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Document inbound forward rules and align the inbound spec with the API - #59

Document inbound forward rules and align the inbound spec with the API#59
mklocek merged 2 commits into
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	$inboxId = $_ENV['MAILTRAP_INBOUND_INBOX_ID'];
	$inboxId = (int) $_ENV['MAILTRAP_INBOUND_INBOX_ID'];

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