scripts/bench-cold-start.py and
scripts/bench-http-outbound.py from our repo.
TL;DR — 30-iteration distribution
The 5-iteration version of this bench gave misleading results (notably, my early E2B numbers were thrown off by sample noise). All numbers below are from 30 sequential cold-start iterations per platform, run on the same machine in the same window.
Reproduce:
scripts/bench-reliability.py.
Each run takes 20–30 s wall-clock per platform, runs 30 sequential
Sandbox.create() → exec("echo ready") → close() cycles, and reports
the full distribution.
Cold-start distribution — head-to-head
The metric customers actually feel: time fromSandbox.create()
until the first echo ready returns. Each row below is 30
sequential iterations per platform — enough samples that the tail
percentiles mean something.
Two findings worth highlighting:
- Podflare wins every percentile. p50 is 3.0× faster than E2B
(the next-best), p95 is 4.4×, p99 is 3.6×, max is bounded under
270 ms while E2B’s max is 888 ms and Blaxel’s is 4 s. The previous
version of this bench, with SDK 0.0.17, showed a 1,741 ms p99 for
Podflare — caused by the SDK’s own
connect=0.8s+retries=2compounding on slow TLS handshakes (three chained ConnectTimeouts add up to ~2.9 s). SDK 0.0.19 widened connect to 2.5 s and dropped retries to 1, killing that self-inflicted tail. SDK 0.0.20 then defaulted toapi.podflare.ai(Cloudflare-edge-routed), which is faster than direct-to-origin from most residential callers because the CF edge PoP is closer than any single region. - All four platforms had 0 errors across 30 iterations. The differentiator is latency distribution, not reliability in the traditional uptime sense.
Pick the metric that matters to your workload
Different production agents care about different parts of the distribution. The “best” platform depends on which tail kills you faster.Why Podflare’s first_exec is 2–48× faster
The firstexec() after create() looks identical from the SDK side,
but the underlying paths are different:
All three competitors run a normal HTTP server inside each sandbox.
Convenient (the SDK can talk plain HTTP), but every exec pays for
TCP + TLS + HTTP framing inside the guest. We use vsock — a direct
host↔guest socket with no TCP overhead — and a binary line protocol.
Round-trip from a hot connection is ~3 ms server-side; the rest is
network between you and the region.
HTTP outbound — what your agent actually feels
Inside-the-sandboxcurl against two reliable targets, 5 runs each.
(Earlier benches included httpbin.org but kept getting 10-second
outliers from all four platforms — that’s httpbin’s per-source-IP
rate limit, not platform speed.)
Two takeaways:
- GitHub-flavored workloads (the long tail of agent traffic —
pip install,npm install, GitHub API, Hugging Face, etc.) all land within ~70 ms of each other. Geography is the whole story; pick a region close to GitHub’s Azure us-east peering. - Cloudflare trace shows raw network speed. Daytona’s 21 ms is fastest because their colo happens to be one hop from Cloudflare’s Ashburn PoP. Differences here are small absolute numbers.
Out-of-the-box experience
Blaxel’s bare-Alpine choice is interesting: smaller image, faster
boot, smaller attack surface. But every workload needs
apk add for
basics like curl, python, git before doing real work — every
fresh sandbox pays for that bootstrap.
Forking and persistent state
Cold-start isn’t the whole story. AI-agent workloads also fork (try N branches in parallel) and persist (resume a working session later). This is where the gap widens.fork() is the genuinely differentiated primitive. Most LLM-agent
patterns (tree-of-thought, multi-attempt code synthesis) want N
children that all start from the parent’s exact mid-flight state. On
container platforms you’d docker commit (~seconds) and docker run N (~seconds × N). On Podflare that’s parent.fork(n=5) — a
copy-on-write diff snapshot + N parallel microVM spawns in 80 ms
p50, total.
See Performance for the breakdown of
what fork() does in those 80 ms.
Architecture comparison
License
If you’re building on top of one of these and might fork it later,
license matters. Daytona’s AGPL is genuinely restrictive for
commercial use; E2B’s Apache-2.0 is permissive; Blaxel and Podflare
are proprietary.
Free-tier limits
Honest comparison: Podflare’s free tier is more conservative on
per-sandbox limits. Tradeoff: lower abuse risk (1 GB ceiling makes
crypto mining unprofitable without separate detection), at the cost
of less headroom for free-tier experimentation. Pro tier opens up
to 4 GB per sandbox, 50 concurrent, 8-hour lifetime.
Production-choice ranking — by axis (30-iter)
When each one wins
- Latency-sensitive interactive agents (default case) →
Podflare. Wins p50 (153 ms), p95 (170 ms), p99 (236 ms), and max
(263 ms) — the only platform under 300 ms at every percentile. Native
fork()for tree-of-thought patterns. Persistent Spaces survive full VM memory across restarts. Requires SDK ≥ 0.0.20 — 0.0.17 through 0.0.18 have a ~1.7 s p99 tail caused by the SDK’s own tight-connect + retries=2 compounding (fixed in 0.0.19); 0.0.20 then defaulted toapi.podflare.aifor edge-routed latency. - GitHub-heavy workloads where outbound to Azure us-east matters → E2B. Their us-east colo wins HTTP outbound to GitHub at 25 ms (vs ours/others at 85–93 ms). Apache-2.0 lets you self-host for compliance.
- Self-hosted on existing Docker/k8s infrastructure → Daytona. Pay the AGPL toll only if you’ll never fork the runtime; the Docker/Sysbox isolation is meaningfully weaker than a microVM if your threat model includes adversarial guest code.
- Minimum-image, minimum-RAM workloads with your own bootstrap → Blaxel. Alpine base + 627 ms p50 is fine if your workload pre-warms with its own deps. Smallest attack surface.
Reproduce these numbers
All bench scripts are in our repo. They take an SDK API key for each platform and run identical workloads.bench-reliability.py run does 30 sequential
Sandbox.create() → exec("echo ready") → close() cycles per platform
and prints the full distribution (min / p50 / p90 / p95 / p99 / max /
mean / spread). No special flags, no warmup-and-discard tricks.
If your numbers differ meaningfully from ours, send us the bench
output and the SDK version you ran — we treat regression reports as
P0. Our job is for these numbers to stay honest, not for our
marketing to claim things the bench can’t reproduce.
Methodology
- Date: April 2026
- Client: macOS laptop on residential wifi, west-coast US
- Podflare endpoint:
api.podflare.aiwith SDK 0.0.20 (Cloudflare-edge-routed — haversine-picks the nearest origin server-side per-request; from this machine that’s us-west) - E2B endpoint:
e2b_code_interpreterSDK default (single GCP/AWS region, likely us-east4) - Daytona endpoint:
daytonaSDK default (single region per account; ours landed near IAD) - Blaxel endpoint:
blaxelSDK withBL_REGION=us-pdx-1andimage=blaxel/base-image:latest - Sandbox spec: each platform’s default — 1 GB / 1 vCPU on all four
- Bench iterations: 30 cold starts per platform, sequential, no
parallelism. Each iteration is a complete
Sandbox.create() → exec("echo ready") → close()/kill()/delete()cycle. We report the full distribution because the 5-iteration version of this bench gave misleadingly noisy results — particularly for E2B, whose median moved from 2,504 ms (5 samples) to 442 ms (30 samples). Sample size matters.

