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Smart Sending Infrastructure & Sharding

Our proprietary sharding engine rotates outgoing volume across multiple accounts in a strict round-robin sequence, mimicking natural human behavior to protect your sender reputation.

Feature Breakdown

FT-INFRA-001

Multi-Provider SMTP Relay

Relay marketing messages securely using Google Workspace, Microsoft 365, or custom SMTP servers, with automatic STARTTLS encryption enforced on port 587.

Technical Capabilities:

Connect to Gmail, Outlook, or corporate SMTP hosts seamlessly.
Enforce STARTTLS on port 587 to prevent packet snooping or modifications.
Store credentials securely inside an AES-256 encrypted MongoDB vault.
Avoid repeated connection handshake delays via SMTP connection pooling.
FT-INFRA-002

Infrastructure Sharding Engine (Round-Robin)

Distribute your campaign volume evenly across all active sending accounts using atomic Redis pointers to prevent any single account from triggering spam volume thresholds.

Technical Capabilities:

Implements atomic Redis INCR pointer for race-condition-free operation.
Cycles through ready accounts in sequence: (pointer + 1) % active_pool.
Automatically skips cool-down, unauthorized, or rate-limited addresses.
Auto-pauses the campaign and alerts you if all sending accounts go offline.
FT-INFRA-003

Randomized Jitter Delay (Anti-Spam Timing)

Ensure natural sending patterns by applying random, non-repeating delays between consecutive messages in the queue.

Technical Capabilities:

Delays individual dispatches randomly between 25 and 45 seconds.
Calculates jitter at job creation and bakes it into BullMQ delayed jobs.
Saves worker threads from blocking or idling, allowing massive scalability.
Keeps average cadence to 80–144 emails/hour, well below spam triggers.
FT-INFRA-004

Automated Account Cool-Down

Protect temporary connection errors and rate-limiting blocks by auto-throttling affected accounts for 60 minutes.

Technical Capabilities:

Triggers instantly on SMTP error codes 421 or 429.
Saves status using an expiring Redis key (3,600s TTL) for auto-recovery.
Skips the throttled account from the active round-robin sharding rotation.
Restores status to READY automatically when the cool-down timer expires.
FT-INFRA-005

UTC Daily Send Limit Reset (Cron Job)

Align with major ESPs like Google and Microsoft by resetting account daily quotas at midnight UTC.

Technical Capabilities:

Executes atomically at 00:00 UTC daily using a scheduled background cron.
Updates counters in Redis cache and MongoDB persistence simultaneously.
Enables rate-limited accounts to rejoin the send pool immediately after reset.
Maintains absolute transactional integrity during batch quota updates.

Spec Sheet

Worker Queue EngineBullMQ + Redis
Relay ProtocolSMTP with STARTTLS
Encryption CipherAES-256-CBC
Rotational ConcurrencyStrict Atomic Round-Robin

Need a Deep Dive?

See exactly how this module manages background queues, encryption, and delivery logic in our sequence flowchart.

View technical guide

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