Nylas vs. Aurinko: Choosing a Unified API for Gmail and Microsoft 365
Nylas and Aurinko solve the same initial problem: giving your application one API surface for Gmail and Microsoft 365 instead of two provider-specific integrations. The more consequential difference is what comes after you connect an account—how you detect changes, maintain local mailbox state, recover from missed events, and propagate actions back to the provider.
If you are choosing between them, evaluate the synchronization contract, not just the list of supported endpoints.
The Common Ground: Unified Access, Not Automatic Synchronization
Both products provide a unified email API for reading messages, sending mail, updating supported message state, and receiving notifications of mailbox changes. Both also extend beyond email.
That shared abstraction reduces provider-specific integration work, but it does not eliminate your application’s synchronization responsibilities.
A unified API standardizes access to mailbox data. A synchronization system keeps your application’s representation of that data consistent over time.
For example, an API may let you mark a message as read. Your application must still decide:
- When to update its local record.
- How to handle a failed or delayed write.
- How to process the notification caused by its own write.
- What to do if someone changes the same message directly in Gmail or Outlook.
- How to detect and repair a missed change.
This distinction matters especially if “sync” means maintaining a durable local copy of mailbox state, rather than simply fetching messages when a screen loads.
The Main Difference: How You Build the Change Pipeline
The strongest architectural distinction in the documented approaches is between Nylas’s emphasis on normalized message access and webhooks, and Aurinko’s explicit incremental-sync methods.
| Dimension | Nylas | Aurinko |
|---|---|---|
| Email access | Normalized Messages API across connected providers | Unified Email API across connected providers |
| Documented sync emphasis | Message webhooks, historical backfill, and application-maintained local state | Explicit incremental retrieval of updated and deleted messages, alongside webhooks |
| Webhook setup | Documents a webhook subscription covering connected providers | Uses resource subscriptions; its documentation describes Cloud Pub/Sub configuration for native Gmail push |
| Adjacent capabilities | Email, calendar, contacts, and scheduling | Email, calendar, contacts, and tasks; separate BrightSync business-system integrations |
| Best initial evaluation fit | A webhook-led implementation across providers | A design centered on explicit incremental change retrieval, including deletions |
These are differences in documented emphasis, not proof that either product cannot support another architecture. You should verify the exact endpoints, event coverage, and recovery behavior available in the API version and plan you intend to use.
Nylas: Webhook-Led Local State
Nylas’s multi-provider synchronization guidance emphasizes a normalized Messages API and message webhooks. A typical application architecture therefore looks like:
- Connect the mailbox.
- Backfill the historical messages your application needs.
- Receive message-change notifications.
- Fetch or apply the relevant changes.
- Maintain your application’s local representation.
The appeal is operational simplicity: your application can use a common webhook integration across connected providers instead of implementing each provider’s notification mechanism separately.
However, webhook delivery is not itself a consistency guarantee. Your design still needs a recovery path for outages, failed processing, duplicate notifications, and gaps between historical backfill and live change handling.
Do not assume particular delivery or ordering guarantees without checking the documentation. The important evaluation question is:
If your application stops processing notifications for an hour, how does it establish that its local mailbox state is correct afterward?
Aurinko: Explicit Incremental Change Retrieval
Aurinko exposes incremental-sync methods for fetching updated and deleted messages in addition to webhook notifications.
That separation can be useful when you want notifications to trigger work while an incremental retrieval mechanism determines what actually changed:
An explicit deleted-message feed is particularly relevant to applications that persist message records locally. Fetching the current set of messages is not necessarily enough to discover which previously stored records should disappear.
Nevertheless, “incremental sync” is not a complete specification. Before relying on it, establish:
- What synchronization state your application must persist.
- How that state advances.
- What happens when it becomes invalid or too old.
- Whether and how changes are paginated.
- What deletion means for the synchronized resource.
- How recovery interacts with a new historical backfill.
These are evaluation questions, not assumptions about Aurinko’s implementation. An explicit change feed makes the synchronization model easier to inspect; its exact guarantees still determine whether it fits your system.
Webhooks: Compare Setup and Recovery Separately
Nylas documents a webhook subscription covering connected providers. Aurinko uses resource subscriptions, and its documentation describes Cloud Pub/Sub configuration for native Gmail push.
That difference can affect deployment effort, but it needs careful interpretation. A native Gmail push setup requirement does not, by itself, establish that every Aurinko integration requires the same configuration. Confirm which notification path applies to your intended deployment.
You should evaluate two separate properties:
| Property | What to verify |
|---|---|
| Setup complexity | Required subscriptions, provider-side configuration, credentials, and infrastructure |
| Recovery capability | How your application catches up after notifications are delayed, missed, or unsuccessfully processed |
The simplest webhook setup is not automatically the strongest synchronization design. Conversely, additional setup may be acceptable if the resulting change-retrieval workflow fits your reliability requirements.
“Two-Way” Has More Than One Meaning
For mailbox synchronization, two-way usually means both:
- Mailbox changes become visible in your application.
- Supported actions in your application are written back to the mailbox.
Both vendors’ unified APIs provide read and write capabilities. But write access does not mean that arbitrary edits to your local database automatically propagate to Gmail or Microsoft 365. You must explicitly map application actions to supported API operations.
Aurinko Unified API Is Not BrightSync
Aurinko’s Unified Email API and its separately priced BrightSync product should not be treated as interchangeable.
BrightSync’s described email-logging capability is one-way logging into a CRM. That is a different workflow from bidirectional mailbox synchronization.
Logging an email into a CRM does not imply that editing the CRM record will modify the original message in Gmail or Outlook.
If you need mailbox actions—such as changing read state, moving messages, or deleting them—evaluate the unified API operations and build the corresponding synchronization logic. Do not select BrightSync on the assumption that CRM record edits automatically become mailbox edits.
Normalization Does Not Erase Provider Semantics
Gmail’s labels and Outlook’s folder model are not identical. A normalized API can give you a common interface, but you still need to establish what a “move” means on each provider.
Similarly, distinguish:
- Removing a message from a particular view.
- Archiving it.
- Moving it to trash.
- Permanently deleting it.
For a local cache, these distinctions determine whether you update membership, change message state, or remove the local record. Test the behavior rather than inferring it from a shared endpoint name.
Capabilities and Pricing Beyond Email
Nylas offers a broader packaged platform spanning email, calendar, contacts, and scheduling. Aurinko offers email, calendar, contacts, and tasks, alongside BrightSync business-system integrations.
The relevant distinction is not breadth alone. If tasks are central to your product, Aurinko deserves an early trial. If packaged scheduling is central, Nylas deserves one.
Treat Listed Prices as a Starting Point
The published rates cited for this comparison were:
| Product | Listed starting price |
|---|---|
| Nylas | Free for 5 connected accounts; Essentials at $15/month for 10 accounts, then $2.25 per additional account |
| Aurinko Unified API | Starts at $1/account/month, with a data-transfer tier; higher-transfer tiers cost more |
Verify current terms before budgeting; these figures are not a live quote. Nylas’s pricing page is the appropriate starting point for its current plans.
Compare prices against the same workload, including:
- Connected-account count.
- Historical backfill depth.
- Mailbox change volume.
- Payload and attachment transfer.
- Required capabilities and plan limits.
A low per-account starting rate may not predict the cost of a transfer-heavy application. Equally, a slightly higher platform cost may be justified if it materially reduces integration and maintenance work.
Run the Same Trial Against Both Products
The most useful proof of concept is a controlled behavioral test, not a successful first API request.
Start with these four cases on both Gmail and Microsoft 365:
| Case | Mailbox-to-application test | Application-to-mailbox test |
|---|---|---|
| New message | Confirm discovery and local insertion | Send through the API and verify the mailbox result |
| Read-state change | Change read state in the provider and observe it locally | Change it in your application and verify provider state |
| Move | Move or relabel a message and inspect the normalized result | Apply your application’s move operation and inspect provider behavior |
| Deletion | Verify how removal is reported and represented locally | Verify the precise effect of your application’s delete action |
Then repeat relevant cases with notification processing temporarily disabled. Measure propagation latency, API work, transferred data, and the steps needed to restore consistency.
Which Should You Trial First?
Trial Nylas first if your priority is a straightforward webhook-led integration across providers, particularly when its scheduling and broader platform capabilities are also valuable.
Trial Aurinko first if explicit incremental retrieval of updated and deleted messages, tasks support, or its transfer-tier pricing model is especially attractive.
The final choice should follow demonstrated behavior. Select the product whose change-detection, write, and recovery contracts let you maintain correct local state with the least operational complexity—not merely the product that makes the first mailbox connection easiest.