* feat(langfuse): migrate the sdk callback to langfuse v4
Replace the v2 trace()/generation()/span() calls with SDK v4 observations exported over OpenTelemetry, with one isolated tracer provider per Langfuse credential set, a discarding exporter for mock mode, and v4 trace and observation id normalization. Keeps the session-header trace provenance logic from main so each call under a session alias still gets its own trace
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): drop the always-true prompt client check now that v4 get_prompt is non-optional
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* test(langfuse): isolate the e2e sync test from cached clients and log the real sdk major
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): type the slack trace-url lookup and drop dead v2 test shims
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* test(slack): cover the langfuse trace url built from the logger host
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* build(docker): pin langfuse to the locked 4.15.2 in the pip image
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): hash all-zero trace and observation ids instead of passing them through
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* feat(langfuse): honour caller generation ids and assert v4 OTLP exports in legacy tests
v2 accepted generation(id=...). v4 derives the observation id from the OTel
span id, so the isolated tracer provider now carries an id generator that
hands out the id start_generation asked for through a context variable, and
the callback passes the resolved generation_id metadata into it.
The legacy e2e suite patched httpx.Client.post and compared v2 ingestion
batches; it now patches requests.Session.post, decodes the OTLP protobuf
and compares the exported generation against regenerated fixtures. The
local readback test replaces the removed get_generations() with
api.observations.get_many() and polls Langfuse Cloud instead of sleeping.
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): read the sdk version header from package metadata
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): propagate trace_metadata as trace-level attributes in v4
v2 wrote trace(metadata=...) onto the trace object. In v4 the trace only
carries what the observations propagate, so a continuation request with
update_trace_keys=["trace_metadata"] updated the generation's metadata
while the trace kept its stale values. Coerce each entry to the SDK's
string limit and hand it to propagate_attributes(metadata=...).
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): propagate interrupts raised during deferred client teardown
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): honor ssl_verify=False and SSL_VERIFY on the v4 OTLP exporter
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): fall back to the default CA when the configured bundle path is missing
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): renew the client when eviction lands before the callback lease
The cache can evict a logger between handing it to the callback and the callback taking its
lease. Such a lease now hands back a fresh client acquired through the same parameters, so that
callback exports through a live tracer provider instead of one teardown already shut down.
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): emit litellm_call_id and response_id as generation metadata
v2 put the provider response id inside the generation id. v4 observation ids are 16 hex chars derived from that string, so the ids move to generation metadata to keep generations searchable by response id
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): read the response id through a typed protocol
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): do not claim trace root when continuing an existing trace
Langfuse derives a trace's name and I/O from any observation flagged
langfuse.internal.as_root, so a request carrying existing_trace_id
renamed the trace to the generation name and replaced the trace input
and output on every continuation. v2 only updated the keys listed in
update_trace_keys. Continuations now export as plain children of the
remote parent and keep the explicit langfuse.trace.* attributes for the
fields they do want changed.
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): iterate lease renewal instead of recursing, monkeypatch update_trace_keys flag in tests
The recursive lease fallback tripped tests/code_coverage_tests/recursive_detector.py; the renewal
candidates are now walked with itertools.chain. The six update_trace_keys tests set the litellm
global through pytest monkeypatch so the TQ008 budget stays within its ceiling
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): retry raised OTLP exports and honor LANGFUSE_TIMEOUT
The OTLP http exporter only retries 429 and 5xx; a connect or read timeout
propagates and BatchSpanProcessor drops the batch. Wrap the exporter in
RetryingSpanExporter (three backoff retries, as the v2 consumer did) and
build it on every path so the default and private-CA deployments share the
same channel, timeout and retry behaviour
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): sample on a hash of the full trace id and tolerate bad LANGFUSE_SAMPLE_RATE
TraceIdRatioBased reads the low 64 bits of the trace id. litellm trace ids are
UUIDs, whose variant bits sit at the top of that word, so every fractional rate
up to 0.5 dropped all traces. A SHA-256 of the full id gives an unbiased,
deterministic decision. Values outside [0, 1] or non numeric now warn and export
everything instead of raising during callback construction, which surfaced as a
500 on the first request of each worker
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): put the Langfuse trace link back into Slack alerts
The proxy registers LangfusePromptManagement for callbacks: ["langfuse"], so the alert helper never saw the literal "langfuse" string and returned before looking up the trace id, and the prompt management logger never stored the trace id it got back from log_event_on_langfuse. Recognize LangFuseLogger instances in the callback list, record the returned trace id in the shared service trace id cache, and skip the link when no trace id arrives
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* chore(deps): relock langfuse 4.15.2 and opentelemetry 1.33.1 on current main
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* chore(langfuse): mark the deliberate blind except in client teardown for the strict ruff gate
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): pass the resource attributes mapping straight to Resource.create
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): warn about ignored UPSTREAM_LANGFUSE_* on the shared client init path too
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): normalise the OTLP export path so a trailing host slash never yields a double slash
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): nest guardrail and grounding spans under the generation
Langfuse v4 derives the trace name and I/O from every observation marked as_root, and the one with the latest start time wins. Guardrail and grounding spans used to claim root next to the generation, so a post_call guardrail could replace the model's request and response on the trace with its own. Only the generation claims root now; the sibling spans become its children
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): rebuild the cached bundle when mock mode or sample rate changes
The SDK keys resource bundles on the public key alone, so a bundle built with the discarding exporter for LANGFUSE_MOCK, or with an earlier LANGFUSE_SAMPLE_RATE, was handed back to a client that asked for a live exporter or a different rate. Compare both when deciding whether the cached bundle is still valid
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): keep trace_public true when a guardrail span is exported
Langfuse folds langfuse.trace.public across every observation in the trace and reads a missing attribute as false, so a guardrail child span without the flag turned a trace_public: true request private on Langfuse Cloud. Child spans now repeat the generation's value
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): emit observations as plain OTel spans, keep the SDK for prompts and auth
The callback now owns an isolated TracerProvider and OTLP exporter and builds generation and child spans with public OpenTelemetry APIs plus the LangfuseOtelSpanAttributes constants. Caller trace ids, generation ids, parent observation ids and historical start and end times are honoured through the OTel id generator, remote SpanContext and explicit span timestamps, so no private Langfuse SDK tracing handle is used any more. The Langfuse client stays only for get_prompt and auth_check
This also resolves the gauntlet findings on the previous draft: fresh traces start from an empty context so caller application spans are never stamped, the Slack trace link is read from the request logging state instead of constructing a logger per alert, a truthy non-mapping trace_metadata is serialized instead of raising, trace_input and trace_output land on the root generation, discarding a cached client is done under the lock, and the prompt cache no longer leaks a task manager because the client cache no longer tears down shared providers
Fixtures under tests/logging_callback_tests lose the SDK-private langfuse.internal.as_root marker; every other exported attribute is unchanged
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): hand the SDK client a validated sample rate so an unusable LANGFUSE_SAMPLE_RATE no longer breaks the callback
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): gate the SDK version before importing the OTel module in prompt management
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): flush every export channel on proxy shutdown and use the callback's host in Slack trace links
The shutdown hook imported litellm.utils.langFuseLogger, a global the callback registry never assigns, so a graceful restart dropped the spans still queued in the batch processors. Shutdown now calls flush_langfuse_tracing, which force-flushes every acquired channel. The Slack alert link falls back to the registered LangFuseLogger's langfuse_host when the request carries no dynamic host, and the export endpoint tests pin that scheme-relative or absolute LANGFUSE_OTEL_TRACES_EXPORT_PATH values stay on the configured host
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): store resolved credentials on LangfusePromptManagement
The Slack alert trace link reads langfuse_host from every registered LangFuseLogger. Prompt management subclasses it without calling the parent constructor, so it never set the attribute and the alerting handler crashed before posting
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): flush every export channel concurrently under one shutdown deadline
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): flush export channels on daemon threads so a stuck channel cannot hold up interpreter exit
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): own the tracer config and drop the SDK client for prompts and auth
The callback's TracerProvider now sets its sampler, span limits and id generator explicitly so unrelated OTEL_* variables no longer change what Langfuse receives, and trace metadata is written once on the trace instead of folded into the generation, which kept input and output under the attribute cap. Spans are emitted under the langfuse-sdk scope so Langfuse renders them natively, the batch processor queues 100k spans and honors LANGFUSE_FLUSH_AT, and the proxy shutdown flush runs off the event loop with a 10s deadline and logs a miss.
Prompts, auth_check and the project id now go through LangfuseAPI directly with a litellm-owned TTL cache, so no Langfuse() client is built and a host application's client on the same public key is left alone. Dead attributes, the unreachable exporter branch and the export list are cleaned up, and the client-budget eviction behavior is documented.
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): export OTLP spans and fetch prompts through litellm's HTTPHandler instead of a private requests session
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): gate the SDK version before importing the tracing module and retire unheld export channels
An installed v2 SDK used to fail inside the langfuse_sdk import and surface as "Langfuse not installed"; the version check now runs first so v2 users get the upgrade message, and only PackageNotFoundError means the package is missing
Export channels are now leased per credential set: acquire adds a holder, LangFuseLogger.stop (called by DynamicLoggingCache on expiry) releases one, and a channel with no holders is flushed and shut down after a 60 s grace, so rotating key or team credentials no longer grows one batch thread per credential set for the life of the process
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): end the generation when a child span fails, take the client slot last, keep prompt cache keys structured
Generation spans now end in a finally block so a bad guardrail or provider entry cannot strand the trace. The logger acquires its export channel and REST client before counting a client slot and releases the channel synchronously if the REST client fails to build, so retries after a bad config do not exhaust the budget. LANGFUSE_TIMEOUT accepts decimals for the REST client like it already did for OTLP export. The prompt cache keys on (name, version, label) so a missing label and the literal label None stay apart
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): claim the cache entry before releasing its slot and channel hold on eviction
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): coerce generation names, keep v2 release, timeout and retry defaults, refresh stale prompts off the loop
A non-string metadata generation_name reached the OTLP encoder and took the whole batch down; it is now exported as its text and the exporter drops only the span the encoder rejects. LANGFUSE_RELEASE falls back to the deploy platform's commit variable again, the export deadline is back to the v2 default of 20 s and LANGFUSE_MAX_RETRIES sizes the retry ladder. An expired prompt is served at once while one background thread refreshes it, a re-acquired export channel cancels the pending retire timer, and flush reports delivery rather than a drained queue
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* test(proxy): assert the current Langfuse shutdown flush warning
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): keep host OTel resource out, carry big metadata ints, tolerate bad flush and TTL env, stamp trace I/O under a parent
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): name a malformed prompt cache TTL before the SDK import, keep metadata ints JSON safe, retry every 5xx export
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): name the auth check failure, split a 413 export, wire LANGFUSE_DEBUG, stamp error output under a parent, send the ingestion version header
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): honor LANGFUSE_DEBUG on the callbacks path, cap retry backoff, name the auth failure status and body
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): cap LANGFUSE_MAX_RETRIES at 1000 so an absurd value cannot stall callback init
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): fold 413 halving into bounded rounds instead of recursion
The code-quality recursive-function gate flagged LangfuseSpanExporter.export. A batch of n spans settles within n.bit_length() halving rounds, so the split is a reduce over a frozen round state with the same posts, logs and results. The TTL gate test now asserts the gate returns without raising
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): truncate a single oversized span like v2 instead of dropping it, no retries on REST auth and project lookups
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): write the metadata truncation marker under a flattened key so Langfuse keeps it
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* test(langfuse): patch the HTTPHandler export path and sync the metadata fixture and lease registry with the v4 callback
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* refactor(langfuse): give the 413 split helpers a single explicit return path
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): url-encode prompt names and fetch cold prompts without client retries
A cold get_prompt runs inline on the event loop; the generated v4 client's default two retries slept through
Retry-After (up to 60 s per attempt) and held the loop. The wrapper also passed the raw name into
api/public/v2/prompts/{name}, so 'what?' fetched prompt 'what' and folder names left the route. Quote the
name with safe='' like the v4 SDK's own get_prompt and pass max_retries=0 like the projects.get calls
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* fix(langfuse): retry a cold prompt miss once and drop upstream headers from prompt errors
A cold prompt fetch makes one immediate second attempt after a 5xx or a
transport failure, as the v2 client did, still with the generated client's
sleeping retries and Retry-After handling off so the event loop never stalls.
A failed fetch raises LangfusePromptError carrying only the status and body,
so the proxy no longer forwards Langfuse's response headers to its client
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* test(langfuse): stub the logger in the health auth_check test instead of dialing a closed port
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* test(langfuse): integration test for OTLP v4 delivery and prompt fetch through a real proxy
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* build(docker): keep the pip image's langfuse and otel pins on the v2 line its litellm 1.83.0 wheel expects
The image validates the published PyPI artifact, whose langfuse callback still
reads langfuse.version, so the 4.15.2 pin broke that callback. The pins move
together with the next LITELLM_VERSION bump. Also rewords the trace_version
precedence test docstring: v2 carried two version fields, v4 has one per span
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---------
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
|
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|---|---|---|
| .cargo | ||
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| ci_cd | ||
| cookbook | ||
| db_scripts | ||
| docker | ||
| enterprise | ||
| examples | ||
| gateway | ||
| helm | ||
| litellm | ||
| litellm-proxy-extras | ||
| litellm-rust | ||
| migrations | ||
| packaging/homebrew | ||
| scripts | ||
| terraform | ||
| tests | ||
| ui | ||
| vscode-extension | ||
| .dockerignore | ||
| .env.example | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitguardian.yaml | ||
| .gitignore | ||
| .grype.yaml | ||
| .npmrc | ||
| AGENTS.md | ||
| ARCHITECTURE.md | ||
| basedpyright-code-budget.json | ||
| codecov.yaml | ||
| CONTRIBUTING.md | ||
| cosign.pub | ||
| docker-compose.hardened.yml | ||
| docker-compose.yml | ||
| Dockerfile | ||
| GEMINI.md | ||
| LICENSE | ||
| license_cache.json | ||
| Makefile | ||
| mcp_servers.json | ||
| model_prices_and_context_window.json | ||
| model_prices_and_context_window.schema.json | ||
| osv-scanner.toml | ||
| package-lock.json | ||
| package.json | ||
| policy_templates.json | ||
| prometheus.yml | ||
| provider_endpoints_support.json | ||
| proxy_server_config.yaml | ||
| pyproject.toml | ||
| pyrightconfig.json | ||
| qa_sticky_session.sh | ||
| README.md | ||
| render.yaml | ||
| router_plugins.json | ||
| ruff-strict-budget.json | ||
| ruff-strict.toml | ||
| ruff-tests.toml | ||
| ruff.toml | ||
| rust-toolchain.toml | ||
| schema.prisma | ||
| security.md | ||
| taplo.toml | ||
| test-quality-budget.json | ||
| type-discipline-budget.json | ||
| uv.lock | ||
| whitelisted_bedrock_models.txt | ||
🚅 LiteLLM
LiteLLM AI Gateway
Open Source AI Gateway for 100+ LLMs. Self-hosted. Enterprise-ready. Call any LLM in OpenAI format.
LiteLLM Proxy Server (AI Gateway) | Hosted Proxy | Enterprise Tier | Website
What is LiteLLM
LiteLLM is an open source AI Gateway that gives you a single, unified interface to call 100+ LLM providers — OpenAI, Anthropic, Gemini, Bedrock, Azure, and more — using the OpenAI format.
Use it as a Python SDK for direct library integration, or deploy the AI Gateway (Proxy Server) as a centralized service for your team or organization.
Jump to LiteLLM Proxy (LLM Gateway) Docs
Jump to Supported LLM Providers
Why LiteLLM
Managing LLM calls across providers gets complicated fast — different SDKs, auth patterns, request formats, and error types for every model. LiteLLM removes that friction:
- Unified API — one interface for 100+ LLMs, no provider-specific SDK juggling
- Drop-in OpenAI compatibility — swap providers without rewriting your code
- Production-ready gateway — virtual keys, spend tracking, guardrails, load balancing, and an admin dashboard out of the box
- 8ms P95 latency at 1k RPS (benchmarks)
OSS Adopters
Netflix |
Features
LLMs - Call 100+ LLMs (Python SDK + AI Gateway)
All Supported Endpoints - /chat/completions, /responses, /embeddings, /images, /audio, /batches, /rerank, /a2a, /messages and more.
Python SDK
uv add litellm
from litellm import completion
import os
os.environ["OPENAI_API_KEY"] = "your-openai-key"
os.environ["ANTHROPIC_API_KEY"] = "your-anthropic-key"
# OpenAI
response = completion(model="openai/gpt-4o", messages=[{"role": "user", "content": "Hello!"}])
# Anthropic
response = completion(model="anthropic/claude-sonnet-4-20250514", messages=[{"role": "user", "content": "Hello!"}])
AI Gateway (Proxy Server)
Getting Started - E2E Tutorial - Setup virtual keys, make your first request
uv tool install 'litellm[proxy]'
litellm --model gpt-4o
import openai
client = openai.OpenAI(api_key="anything", base_url="http://0.0.0.0:4000")
response = client.chat.completions.create(
model="gpt-4o",
messages=[{"role": "user", "content": "Hello!"}]
)
Agents - Invoke A2A Agents (Python SDK + AI Gateway)
Supported Providers - LangGraph, Vertex AI Agent Engine, Azure AI Foundry, Bedrock AgentCore, Pydantic AI
Python SDK - A2A Protocol
from litellm.a2a_protocol import A2AClient
from a2a.types import SendMessageRequest, MessageSendParams
from uuid import uuid4
client = A2AClient(base_url="http://localhost:10001")
request = SendMessageRequest(
id=str(uuid4()),
params=MessageSendParams(
message={
"role": "user",
"parts": [{"kind": "text", "text": "Hello!"}],
"messageId": uuid4().hex,
}
)
)
response = await client.send_message(request)
AI Gateway (Proxy Server)
Step 1. Add your Agent to the AI Gateway — set protocolVersion to 1.0 or 0.3 per agent
Step 2. Call Agent via A2A SDK (requires a2a-sdk>=1.1.0)
import httpx
from a2a.client import A2ACardResolver, ClientConfig, ClientFactory
from a2a.types import Message, Part, Role, SendMessageRequest
from a2a.utils.constants import TransportProtocol
from uuid import uuid4
base_url = "http://localhost:4000/a2a/my-agent" # LiteLLM proxy + agent name
headers = {"Authorization": "Bearer <your-master-key>"} # LiteLLM master key or a virtual key
async with httpx.AsyncClient(headers=headers, timeout=60.0) as http_client:
resolver = A2ACardResolver(httpx_client=http_client, base_url=base_url)
agent_card = await resolver.get_agent_card()
config = ClientConfig(
httpx_client=http_client,
streaming=False,
supported_protocol_bindings=[TransportProtocol.JSONRPC, TransportProtocol.HTTP_JSON],
)
client = ClientFactory(config).create(agent_card)
request = SendMessageRequest(
message=Message(
message_id=uuid4().hex,
role=Role.ROLE_USER,
parts=[Part(text="Hello!")],
)
)
async for event in client.send_message(request):
populated = event.ListFields()
if populated and populated[0][0].name in ("message", "msg"):
print("".join(getattr(p, "text", "") or "" for p in populated[0][1].parts))
MCP Tools - Connect MCP servers to any LLM (Python SDK + AI Gateway)
Python SDK - MCP Bridge
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client
from litellm import experimental_mcp_client
import litellm
server_params = StdioServerParameters(command="python", args=["mcp_server.py"])
async with stdio_client(server_params) as (read, write):
async with ClientSession(read, write) as session:
await session.initialize()
# Load MCP tools in OpenAI format
tools = await experimental_mcp_client.load_mcp_tools(session=session, format="openai")
# Use with any LiteLLM model
response = await litellm.acompletion(
model="gpt-4o",
messages=[{"role": "user", "content": "What's 3 + 5?"}],
tools=tools
)
AI Gateway - MCP Gateway
Step 1. Add your MCP Server to the AI Gateway
Step 2. Call MCP tools via /chat/completions
curl -X POST 'http://0.0.0.0:4000/v1/chat/completions' \
-H 'Authorization: Bearer <your-master-key>' \
-H 'Content-Type: application/json' \
-d '{
"model": "gpt-4o",
"messages": [{"role": "user", "content": "Summarize the latest open PR"}],
"tools": [{
"type": "mcp",
"server_url": "litellm_proxy/mcp/github",
"server_label": "github_mcp",
"require_approval": "never"
}]
}'
Use with Cursor IDE
{
"mcpServers": {
"LiteLLM": {
"url": "http://localhost:4000/mcp/",
"headers": {
"x-litellm-api-key": "Bearer <your-master-key>"
}
}
}
}
For MCP OAuth, an upstream may advertise dynamic client registration but refuse requests with HTTP 401 or 403. If the provider requires a pre-registered OAuth app, configure its credentials.client_id and, when required, credentials.client_secret on the MCP server. This skips dynamic registration in the gateway sign-in flow. The provider must approve the app for MCP access; reaching its authorization page does not establish that login or tool calls will succeed
Supported Providers (Website Supported Models | Docs)
Get Started
You can use LiteLLM through either the Proxy Server or Python SDK. Both give you a unified interface to access multiple LLMs (100+ LLMs). Choose the option that best fits your needs:
| LiteLLM AI Gateway | LiteLLM Python SDK | |
|---|---|---|
| Use Case | Central service (LLM Gateway) to access multiple LLMs | Use LiteLLM directly in your Python code |
| Who Uses It? | Gen AI Enablement / ML Platform Teams | Developers building LLM projects |
| Key Features | Centralized API gateway with authentication and authorization, multi-tenant cost tracking and spend management per project/user, per-project customization (logging, guardrails, caching), virtual keys for secure access control, admin dashboard UI for monitoring and management | Direct Python library integration in your codebase, Router with retry/fallback logic across multiple deployments (e.g. Azure/OpenAI) - Router, application-level load balancing and cost tracking, exception handling with OpenAI-compatible errors, observability callbacks (Lunary, MLflow, Langfuse, etc.) |
Stable Release: Use docker images with the -stable tag. These have undergone 12 hour load tests, before being published. More information about the release cycle here
Support for more providers. Missing a provider or LLM Platform, raise a feature request.
Deploy on AWS or GCP with Terraform
Run the LiteLLM proxy as a production-ready componentized stack (gateway, backend, UI on separate services; managed Postgres + Redis + object store) using the published Terraform modules. Both modules are on the public Terraform Registry — no auth needed.
AWS — ECS Fargate + Aurora + ElastiCache + ALB
— opens an in-browser shell, already authenticated to your AWS account. Once inside, run:
git clone https://github.com/BerriAI/litellm.git
cd litellm/terraform/litellm/aws/examples/default
cp terraform.tfvars.example terraform.tfvars # edit region/tenant/env
terraform init && terraform apply
Or call the module from your own root config:
# main.tf
terraform {
required_version = ">= 1.6.0"
required_providers {
aws = { source = "hashicorp/aws", version = "~> 5.60" }
}
}
provider "aws" {
region = "us-west-2"
}
module "litellm" {
source = "BerriAI/litellm/aws"
version = "~> 1.89"
region = "us-west-2"
azs = ["us-west-2a", "us-west-2b"]
tenant = "acme"
env = "prod"
# Production: provide an ACM cert. Without one, set allow_plaintext_alb = true
# (dev/trial only).
# acm_certificate_arn = "arn:aws:acm:us-west-2:111122223333:certificate/..."
allow_plaintext_alb = true
}
output "litellm_url" {
value = module.litellm.alb_dns_name
}
terraform init
terraform apply
Provider API keys live in AWS Secrets Manager; reference ARNs via gateway_extra_secrets. Full input list and architecture diagram on the registry page.
GCP — Cloud Run + Cloud SQL + Memorystore + HTTPS LB
Real 1-click. Opens Cloud Shell, clones this repo, and walks you through terraform apply via a built-in DeployStack tutorial — pick the project, the tutorial sets up the Artifact Registry remote repo, writes terraform.tfvars from your answers, and runs apply.
To call the module from your own config instead, Cloud Run can't pull from ghcr.io directly, so first set up a one-time Artifact Registry remote repo backed by GHCR:
gcloud artifacts repositories create litellm \
--location=us-central1 \
--repository-format=docker \
--mode=remote-repository \
--remote-docker-repo=https://ghcr.io \
--project=my-gcp-project
Then:
# main.tf
terraform {
required_version = ">= 1.6.0"
required_providers {
google = { source = "hashicorp/google", version = "~> 6.10" }
google-beta = { source = "hashicorp/google-beta", version = "~> 6.10" }
}
}
provider "google" { project = "my-gcp-project"; region = "us-central1" }
provider "google-beta" { project = "my-gcp-project"; region = "us-central1" }
module "litellm" {
source = "BerriAI/litellm/google"
version = "~> 1.89"
project_id = "my-gcp-project"
region = "us-central1"
tenant = "acme"
env = "prod"
# Replace my-gcp-project with your GCP project ID (same value as project_id above).
image_registry = "us-central1-docker.pkg.dev/my-gcp-project/litellm/berriai"
# Production: provide DNS already pointing at the LB IP for Google-managed certs.
# Without one, set allow_plaintext_lb = true (dev/trial only).
# lb_domains = ["proxy.example.com"]
allow_plaintext_lb = true
}
output "litellm_url" {
value = module.litellm.load_balancer_url
}
terraform init
terraform apply
Provider API keys live in Secret Manager; reference resource IDs (e.g. projects/my-gcp-project/secrets/openai-api-key) via gateway_extra_secrets. Full input list and architecture diagram on the registry page.
Both stacks include
- The full componentized split (gateway / backend / UI as independent services)
- Managed Postgres (writer + reader) and Redis
- Versioned object store for proxy state + file uploads
- An auto-generated
LITELLM_MASTER_KEYin your cloud's secret manager - A one-off migration job that runs
prisma migrate deploybefore the proxy starts - The same
proxy_configsurface as the Helm chart — pass YAML as a typed map
The Terraform modules live at terraform/litellm/aws/ and terraform/litellm/gcp/ in this repo; the registry entries are read-only mirrors updated on each release.
Run in Developer Mode
Services
- Setup .env file in root
- Run dependent services
docker-compose up db prometheus
Backend
- Run
make bootstrap - Start proxy backend:
uv run python litellm/proxy/proxy_cli.py
Frontend
- Navigate to
ui/litellm-dashboard(dependencies were already installed w/make bootstrap) - Start dashboard:
npm run dev
Verify Docker Image Signatures
All LiteLLM Docker images published to GHCR are signed with cosign. Every release is signed with the same key introduced in commit 0112e53.
Verify using the pinned commit hash (recommended):
A commit hash is cryptographically immutable, so this is the strongest way to ensure you are using the original signing key:
cosign verify \
--key https://raw.githubusercontent.com/BerriAI/litellm/0112e53046018d726492c814b3644b7d376029d0/cosign.pub \
ghcr.io/berriai/litellm:<release-tag>
Verify using a release tag (convenience):
Tags are protected in this repository and resolve to the same key. This option is easier to read but relies on tag protection rules:
cosign verify \
--key https://raw.githubusercontent.com/BerriAI/litellm/<release-tag>/cosign.pub \
ghcr.io/berriai/litellm:<release-tag>
Replace <release-tag> with the version you are deploying (e.g. v1.83.0-stable).
Enterprise
For companies that need better security, user management and professional support
Get an Enterprise License Talk to founders
This covers:
- ✅ Features under the LiteLLM Commercial License:
- ✅ Feature Prioritization
- ✅ Custom Integrations
- ✅ Professional Support - Dedicated discord + slack
- ✅ Custom SLAs
- ✅ Secure access with Single Sign-On
Contributing
We welcome contributions to LiteLLM! Whether you're fixing bugs, adding features, or improving documentation, we appreciate your help.
Quick Start for Contributors
This requires uv to be installed.
git clone https://github.com/BerriAI/litellm.git
cd litellm
make install-dev # Install development dependencies
make format # Format your code
make lint # Run all linting checks
make test-unit # Run unit tests
make format-check # Check formatting only
For detailed contributing guidelines, see CONTRIBUTING.md.
📖 Contributing to documentation? The LiteLLM docs have moved to a separate repository: BerriAI/litellm-docs. Please open doc PRs there. Docs are served at docs.litellm.ai.
Code Quality / Linting
LiteLLM follows the Google Python Style Guide.
Our automated checks include:
- Ruff for formatting, linting, and code quality
- basedpyright for type checking
- Circular import detection
- Import safety checks
All these checks must pass before your PR can be merged.
Support / talk with founders
- Schedule Demo 👋
- Community Discord 💭
- Community Slack 💭
- Our emails ✉️ ishaan@berri.ai / krrish@berri.ai
