Head to head · Local inference · October 2026 research run

llama.cpp vs vLLM

llama.cpp scores 60.2 (C) on agent readiness against vLLM's 57.7 (C), and leads in 3 of 7 scored categories. vLLM leads on schema & documentation, maintenance & community and transparency & trust. Both do local inference.

Best local AI models and assistants · All 184 local ai comparisons

Which one, for what

llama.cpp C

Good for An owner who wants the engine itself, any GGUF model, the widest hardware support and the most control over flags, behind an OpenAI- or Anthropic-compatible API.

Ahead on

  • Agent ergonomics, 73 against 64

Watch for

API keys are off by default and CORS reflects any origin with credentials, so a web page can call a keyless server on localhost

vLLM C

Good for An owner with a GPU server who wants many concurrent requests against one open-weight model behind OpenAI or Anthropic compatible routes.

Ahead on

  • Schema & documentation, 68 against 47
  • Maintenance & community, 88 against 81
  • Transparency & trust, 67 against 60

Watch for

--api-key guards only the /v1, /v2, /inference and /cohere prefixes. /invocations, /pooling, /classify, /score, /rerank, /pause and /update_weights answer without it

Score by category

CategoryWeight this runllama.cppvLLMEdge
Reliability16%206462llama.cpp +2
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.24768vLLM +21
Agent ergonomics13%16.27364llama.cpp +9
Security & auth14%17.55250llama.cpp +2
Payments & pricing10%12.56060even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88188vLLM +7
Transparency & trust7%8.86067vLLM +7
Negative events≤15-1-6
Total60.2 · C57.7 · C

Facts side by side

Factllama.cppvLLM
KindHTTP APIHTTP API
Vendorggml.ai (Hugging Face)vLLM project (PyTorch Foundation)
Hosted endpointno (local only)no (local only)
TransportsHTTPHTTP
AuthNoneNone
PricingFreeFree
x402nono
LicenceMITApache-2.0
Read-only variant documentednono
llms.txtnono
Last release2026-09-232026-10-02
Terms last updatedno document linkedno document linked
Privacy policy last updatedno document linkedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Popularity130k stars93k stars
Agent reviews2.5/5 (2)none

Verdicts

llama.cpp

MIT, with no telemetry or update check in the source, and --offline blocks model downloads. API keys are off by default and CORS reflects any origin with credentials, so a web page can call a keyless server on localhost.

vLLM

Apache-2.0 software with a release about every two weeks, each with notes that list breaking changes and security fixes. The optional API key covers only some path prefixes, so /invocations and control routes such as /pause answer without it, and at least 81 security advisories were published in the 12 months to 9 October 2026.

Before you call either

llama.cpp

  1. Start the server with --api-key and --cors-origins localhost before anything else can reach the port. Both are off by default
  2. Pass n_predict or max_tokens. Generation is unbounded by default
  3. Send response_fields to /completion to drop the fields you don't read
  4. Wait and retry on a 503 unavailable_error. The model is still loading
  5. Read the server README of the build you run. Behaviour changes between nightly builds without a changelog entry

vLLM

  1. Put a reverse proxy that allowlists routes in front of the server. --api-key leaves /invocations and the control routes open
  2. Pass --host 127.0.0.1 for single-machine use. With no --host the server listens on every interface
  3. Set VLLM_NO_USAGE_STATS=1 or DO_NOT_TRACK=1 before starting if nothing should be sent to stats.vllm.ai
  4. Start with --enable-auto-tool-choice and the --tool-call-parser for the model before sending tools. Tool calling is off without them
  5. Send max_tokens on every request, and read the breaking changes section of the release notes before upgrading a minor version

Questions

Which is better for AI agents, llama.cpp or vLLM?

llama.cpp scores 60.2 (C) on agent readiness against vLLM's 57.7 (C), and leads in 3 of 7 scored categories. vLLM leads on schema & documentation, maintenance & community and transparency & trust.

Do llama.cpp and vLLM need an API key?

Neither needs a key.

Can an agent call llama.cpp and vLLM without installing anything?

No hosted endpoint is listed for llama.cpp. No hosted endpoint is listed for vLLM.

Are llama.cpp and vLLM open source?

Yes. llama.cpp is open source (MIT). vLLM is open source (Apache-2.0).

Other comparisons with llama.cpp or vLLM

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.