Blog
Notes from the
honest side of email
Deliverability, honest analytics and outreach craft — written in plain language, with no growth-hack snake oil.
Earlier articles
103 articles
Developer6 min
The job pattern: how to bulk-import contacts into Norbelys correctly
Importing 20,000 contacts one POST at a time will rate-limit you and hide partial failures. Here's the job pattern — create a job, poll for progress — and why it exists.
Developer6 min
Typed API errors: handling Norbelys errors without guessing from status codes
A 400 alone tells you nothing useful. How to build error handling around the Norbelys API's structured error shape instead of parsing status codes and hoping.
Developer7 min
Idempotency-Key: stopping a flaky retry from double-firing
What the Idempotency-Key header does on Norbelys's API, why it matters for state-changing POSTs, and what happens to a retried request without one.
Developer7 min
The Norbelys OpenAPI spec: 83 operations, one document
A practical tour of api.norbelys.com/openapi.json: what's in it, how to import it into Postman or Insomnia, and why one spec drives every SDK and the CLI.
DeveloperAnalysis7 min
Why Norbelys's API uses givenName, not first_name
Norbelys's API uses Schema.org fields — givenName, affiliation, sameAs — instead of bespoke names like first_name. The reasoning, plus the mapping table.
Developer8 min
The five patterns behind every Norbelys API endpoint
Every Norbelys REST endpoint is one of five patterns: resource, relationship, view, action, or job. Learn the five and you can predict the whole API.
Deliverability8 min
How Email Warmup Actually Works: Ramps, Replies, and Safety Controls
Learn how email warmup works, what mailbox providers require, and how Norbelys controls volume, replies, sender health, and campaign capacity.
AIBuild note6 min
Run your entire cold-email operation from an AI agent
Norbelys ships a remote MCP server: one URL that hands Claude, Cursor, or your own agent the whole platform as tools — import leads, verify, segment, launch, and monitor without opening a browser tab.
Deliverability3 min
The pre-send cold email checklist: four gates, sixteen checks
Run every campaign through four gates before it sends — domain, list, copy, send settings. Sixteen checks, each with the free tool or the number that verifies it, printable in your head.
Copywriting4 min
Personalization at scale: the ladder from {first_name} to 18% replies
Merge fields aren't personalization — they're mail merge. The four rungs of the personalization ladder with reply-rate data at each level, what each rung costs per prospect, and how to climb without hiring interns.
Prospecting3 min
How to build a cold email lead list that doesn't bounce
A lead list is a pipeline, not a purchase: write the ICP down, source by trigger, verify every address before it teaches Gmail who you are, and build small, specific segments.
Strategy6 min
The AI campaign brief that gets usable cold email instead of sludge
AI can draft cold email, but only if the brief gives it ICP, trigger, offer, proof, constraints and approval rules. Here is the Norbelys-style brief and workflow.