Celesto CI vs GitHub Actions and Blacksmith Benchmarks

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Blacksmith vs GitHub Actions vs Celesto CI: what the benchmarks say

I build Celesto CI. Celesto has a lower paid per-minute rate than both Blacksmith and GitHub's 4-core Linux larger runner. In the snapshot below, Celesto finished the cold builds faster than GitHub's benchmark runner. That's the useful comparison: how long you wait, what a running minute costs, and what those numbers actually measure. What we compared The Celesto CI benchmark repository publishes workflows, results and source run links. This article uses its November 14 comparison, including the November 15 Celesto Docker rerun after a runner disk change. All three rows use Linux x64 runners with 4 vCPU and 16 GB of listed RAM. That is the same listed configuration, not identical hardware. CPU models, disks, regions and host load differ. The workloads are real public projects pinned to commits: Rust: spotify-player, with formatting checks, tests and two Clippy passes. Node/TypeScript: opencode, with a cold Bun install and typecheck. Turbo's local and remote caches are disabled. Docker: PostHog's production image, built with no build cache. Cache: save and restore a 4 GiB file using actions/cache. Queue: start a burst of 15 jobs and measure the median wait from job creation to runner start. Celesto's results come from our repository. GitHub and Blacksmith results come from the RunsOn public benchmark data, using the workloads described in its methodology. RunsOn also sells CI infrastructure, so this is vendor-maintained evidence, not an independent lab test. Build times: Celesto beats GitHub; Blacksmith trades a 6x paid rate for speed Lower is better. Workload GitHub Blacksmith Celesto CI Rust 3m 35s 2m 02s 2m 54s Node/TypeScript 1m 38s 50s 1m 19s Docker 12m 59s 5m 52s 9m 14s Cache save + restore 1m 20s 17s 41s Burst queue, p50 3s 11s 15s Compared with GitHub in this snapshot, Celesto reduced Rust workload time by about 19%, Node/TypeScript by 19%, and Docker by 29%. Blacksmith completed all three builds and the cache test sooner, at 6x Celesto's paid per-minute rate for this listed configuration ($0.008 versus $0.00133333). That is a rate comparison, not a claim that each build costs 6x as much: Blacksmith's shorter runtime offsets part of the rate difference. GitHub had the shortest burst queue wait. These are workload-phase times, not the full time from pushing a commit to getting a green check. Setup, collection and other steps outside the measured phases are excluded. Queue wait is shown separately. Paid rates: Celesto costs less per running minute Here are the published Linux x64 rates for the same listed 4-vCPU / 16-GB configuration, checked November 15, 2026: Provider Paid rate per minute Source GitHub, Linux 4-core larger runner $0.012 GitHub runner pricing Blacksmith, 4 vCPU $0.008 Blacksmith pricing Celesto CI, Large $0.00133333 Celesto CI pricing Celesto's $0.08/hour rate works out to about 89% less per minute than GitHub's 4-core larger runner and 83% less than Blacksmith's 4-vCPU runner. There is an important distinction: the GitHub timing row uses its public-repository standard runner. The $0.012 rate belongs to GitHub's paid 4-core larger-runner SKU. The listed CPU and RAM align, but these results do not establish the performance of that paid SKU. This is a specification-level price comparison alongside a benchmark, not an invoice comparison for the measured GitHub jobs. Also, free usage matters: GitHub's standard runners are free for public repositories, and eligible private-repository usage has an included allowance. Celesto does not beat a $0 bill on price. Blacksmith advertises 3,000 free minutes per month. Celesto offers a one-time $5 trial, but the current trial is Micro-only. It does not cover the Large runner used here. A lower rate is not the whole bill A runner that costs more per minute can finish sooner. A fair cost-per-job comparison needs each provider's full billable runtime, its billing rules, allowances and any extra charges. Multiplying only the build times above by the rates would leave th...

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