Hey everyone. I've been neck-deep in vendor evaluations for our CI pipeline renewal, and as usual, the pricing pages from the big providers left me with more questions than answers. "Pay per minute" sounds simple until you realize everyone's minute is priced differently and comes with a completely different set of included resources and hidden ceilings.
I built a comparison spreadsheet to cut through the fog, and I thought it might save some of you a weekend. My goal was to move beyond the marketing headlines and model the actual monthly invoice based on real usage patterns. The core idea is that you input your own metrics—number of builds per month, average build duration, concurrency needs—and the sheet spits out a projected cost across several vendors.
Here’s what the sheet forces you to compare side-by-side:
* **Effective Price Per Minute:** This isn't the listed price, but the calculated cost after factoring in their minimum billing increments (e.g., 1 minute vs. 10 seconds) and any included "free" minutes.
* **Concurrency Impact:** Some vendors charge a premium for multiple concurrent jobs, which can explode your costs during peak dev periods. This is often the hidden budget-killer.
* **OS & Machine Type Adjustments:** Windows builds typically cost 2x Linux. Need more RAM or CPU? The sheet applies the vendor-specific multipliers.
* **Data Transfer & Artifact Storage:** Often forgotten, these can add a non-trivial line item, especially if you're moving large artifacts or caching heavily.
I started with a baseline of 1500 builds/month at 8 minutes average, with a need for 3 concurrent jobs, and the variance was staggering. One vendor's "low per-minute rate" became the most expensive due to their concurrency fees, while another's seemingly higher rate was more predictable.
I've included columns for:
* The major cloud-based CI platforms (you know the names)
* A rough model for self-hosted runners on a cloud VM, factoring in compute, IT labor overhead, and security patching
* Key non-price factors: vendor lock-in level, typical SLA response times, and their contract flexibility (month-to-month vs. annual commitments)
My personal takeaway so far is that there's no universal "cheapest." It entirely depends on your build profile. High concurrency needs push you toward one model; long, sequential builds favor another.
I've left the sheet editable and added some notes on the assumptions. If you have suggestions for other vendors to add or metrics to model, I'm all ears. Hopefully this gives you a practical starting point for your own procurement review.
— frank
buyer beware, but buy smart
That concurrency point is the real killer, absolutely. We got burned last year scaling up a team - the base per-minute cost looked fine, but we hadn't factored in the 4x multiplier for wanting more than three concurrent jobs on one vendor's plan. Our bill went vertical during a sprint week.
Have you looked into how each vendor handles caching in your model? That can dramatically change effective build minutes. Some treat cached dependencies as a free layer, others meter the storage/network egress, which adds a whole other dimension to the "effective price."
Love the idea of forcing a side-by-side on billing increments. The difference between a 10-second block and a 1-minute minimum can be huge for fast unit test suites.
Automate all the things.