Sequences that optimize while you sleep
Sendbox campaigns let you stack email steps with custom wait windows, run several A/B variants side by side, branch logic with IF/THEN/ELSE rules, and rotate phrasing through spintax. The optimization engine watches performance and quietly benches the variants that underperform. Because each mailbox is permanently tied to its own dedicated IP through sticky hash assignment, none of that sending shares infrastructure with anyone else.
Lambda Group
Campaigns
Campaign | Status | Leads | Sent | Opened | Replied | Positive | Bounced | |
|---|---|---|---|---|---|---|---|---|
SaaS VP Decision Makers | Active | 4,200 | 2,847 | 1,748(61.4%) | 236(8.3%) | 92(39.0%) | 51(1.8%) | |
Series A Founders – West Coast | Active | 1,800 | 1,204 | 784(65.1%) | 133(11.0%) | 61(45.9%) | 19(1.6%) | |
Agency Owners Outreach | Paused | 5,600 | 3,891 | 2,218(57.0%) | 214(5.5%) | 72(33.6%) | 82(2.1%) | |
Enterprise IT Directors | Completed | 7,100 | 5,102 | 3,265(64.0%) | 453(8.9%) | 176(38.8%) | 92(1.8%) | |
RevOps Teams Q1 2025 | Draft | 920 | - | - | - | - | - |
Set it up once, let it run
IF/THEN/ELSE conditions keyed to any variable, so different leads see different messaging depending on their data.
Sendbox flags copy that's gone stale and can regenerate or pause that variant automatically.
Fire off webhooks for lead.created, lead.replied, email.sent, email.opened, and lead.bounced, configured per campaign.
Stop on any reply, stop only on auto-replies, or stop the moment anyone at that company responds — plus CC/BCC and unsubscribe-link controls.
Live campaigns in minutes, not hours
Stack email steps and set wait periods measured in hours or days. Write A/B variants per step (A, B, C, and beyond), branch the copy with IF/THEN/ELSE conditions tied to any variable, and rotate phrasing using spintax like {option1|option2|option3}, nesting included.
Choose which mailboxes carry the sequence. Sendbox spreads the load with round-robin, random, or priority rotation, and automatically works out each lead's timezone from their city or country if that data was imported.
Define a sending window with start and end times, pick your working days, and skip holidays automatically. The optimization engine benches underperforming A/B variants on its own. A reply from any lead halts their sequence the instant it lands.
Run every client's campaigns on infrastructure that's entirely their own. Each mailbox maps to a single IP by MD5 hash permanently, so nobody shares sending reputation with anyone else on the platform.
Spread sends across dozens of connected mailboxes using round-robin, random, or priority rotation. Cap each campaign's sending window so no single mailbox exceeds its daily volume.
Drop in variables like {{firstName}} and {{company}}, plus any custom field you've defined. Layer conditional logic on top so different segments of your list see genuinely different copy.
Every send traced back to your own IP
Dedicated IPs, not a shared pool
Most cold email platforms bunch every customer onto shared sending servers, so one account's spam complaint becomes everyone's deliverability problem. Sendbox assigns dedicated IPs to every account with sticky hash mapping, permanently pairing each mailbox to its own IP. Your sender reputation stays entirely yours.
Sending windows that respect the lead's clock
Sendbox works out each lead's timezone from the country or city on file, then sends only inside the window you configure — with a start time, an end time, chosen working days, and holidays skipped automatically. Your prospect sees the email land during their workday, not yours.
Optimization does the picking for you
Skip babysitting your A/B tests. The optimization engine reallocates volume toward whichever variant is winning and pauses the ones that aren't, based on thresholds you set: minimum sends per variant, minimum days before it acts, and an auto-pause trigger.
Got questions? We've got answers.
Still stuck? Talk to us →There's no hard cap — add as many steps as the campaign calls for, each with its own wait period in hours or days. Most sequences that convert well land somewhere between 4 and 7 steps.
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