What we learn running in production.
No generic “5 tips to boost engagement” posts. We write about architecture decisions, Meta rule changes, real channel cost, and what we found out when something broke.
The WhatsApp 24-hour window: what opens it, what closes it, and where the math goes wrong
Every Cloud API integration runs into the same rule, and most of them get the same piece of it wrong. The window doesn't start when your server processes the webhook — it starts at the timestamp Meta sent inside it.
CCX Engineering · Platform · Channel rules · Aug 19, 2026 · 7 min readRead the featured post
Everything we've published so far.
10 posts. Written by the people who ran the problem — engineering, product, or delivery — not an agency.
WhatsApp template categories: why your utility template became marketing
Meta does not take the category you choose at face value: it checks the content, approves as marketing whatever it thinks is marketing and, since September 2026, re-evaluates approved templates by the messages they send. The category decides the price, the limits and, from 2027, even the API the message goes out through. What separates utility from marketing, how recategorisation gives notice and what to do when it arrives.
CCX Engineering · Platform · Channel rules · Oct 17, 2026 · 15 min read
WhatsApp error 131049: the marketing message Meta decided not to deliver
Error 131049 is not a technical failure, it is not a block on your number and retrying does not fix it. It is Meta saying that this person has already received too much marketing — yours and every other business's — and that resending within 24 hours only returns another 131049. How to read the error, tell it apart from its neighbours, measure its effect on a campaign and prepare for the end of marketing on the Cloud API in 2027.
CCX Engineering · Platform · Engineering · Oct 17, 2026 · 15 min read
WhatsApp coexistence: the Business app and the Cloud API on the same number
You can keep answering from the WhatsApp Business app on your phone and, at the same time, connect the same number to the Cloud API — without giving up the number your customers know or your chat history. Meta calls it onboarding business app users; the market calls it coexistence. What it requires, what changes in the app, the 24 hours you do not get back and what the integration has to do to avoid ruining six months of history.
CCX Engineering · Platform · Channel rules · Oct 17, 2026 · 15 min read
The CCX Messages partner program: 20% every month, a year-end bonus, and we handle the sale
The program fits in one line: A + B. A is 20% of the subscription of every client you refer, every month, for as long as they stay a client. B is a 1% to 4% bonus on everything your portfolio spent on messages during the year. This post shows how the two add up, what counts as a referral and how the money reaches you.
CCX Product · Product · Partnerships · Oct 17, 2026 · 10 min read
RCS got end-to-end encryption. The spec doesn't say how far it reaches.
The GSMA announced E2EE for RCS over MLS, in the same text that covers improvements to business messaging. Anyone filling in a security questionnaire needs to know whether their own traffic sits inside that scope — and neither primary source answers. This is about what to do with an answer that doesn't exist yet.
CCX Engineering · Platform · Channel rules · Aug 29, 2026 · 9 min read
The carrier's answer belongs to you, not to us
When a send fails, the carrier returns a reason. Keeping that reason and handing over only the label turns diagnosis into a support ticket — and moves work onto your team that had already been done. This is about why platforms do that, why we stopped, and what changes on call.
CCX Engineering · Platform · Engineering · Aug 28, 2026 · 8 min read
WhatsApp service message pricing: one goes down, the other never will
On 1 October 2026 Meta starts charging for two things that are free today, and the market is adding them up as if they pulled in the same direction. One of them starts counting toward your volume tier and can make what you already pay cheaper; about the other, Meta wrote in plain words that there will be no tiers at all.
CCX Engineering · Platform · Cost · Aug 26, 2026 · 9 min read
WhatsApp opt-in: what the law requires, what Meta requires, and where the two don't meet
Meeting Meta's policy is not meeting data protection law, and meeting the law won't protect you from a quality-based block. Two sets of rules with different foundations — and treating them as one means finding out the difference at the worst moment.
CCX Operations · Delivery · Operations · Aug 25, 2026 · 6 min read
131047, 131051 and 133010: what the Cloud API means when it rejects your message
Three codes that show up early in any WhatsApp integration, and whose documented names point at the wrong place. One of them blames the recipient when the problem is the sender.
CCX Engineering · Platform · Engineering · Aug 22, 2026 · 8 min readThe WhatsApp 24-hour window: what opens it, what closes it, and where the math goes wrong
Every Cloud API integration runs into the same rule, and most of them get the same piece of it wrong. The window doesn't start when your server processes the webhook — it starts at the timestamp Meta sent inside it.
CCX Engineering · Platform · Channel rules · Aug 19, 2026 · 7 min readThree editorial lines, none of them about us.
If a piece doesn't help someone make a better decision, we don't publish it. Product announcements go to the changelog, not here.
Real engineering
Architecture decisions and trade-offs we took, with the real numbers, not euphemisms.
Channel rules
Meta policy changes, carrier requirements, brand verification. What changes for you and by when.
Cost without euphemism
How each channel's price is built and what makes your bill rise without you noticing.
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