DROP-IN SDKHARD SPENDING CAPSPROMPTS STAY LOCAL
Your agent can spiral.
Your LLM bill can't.
Solwyn wraps the LLM client you already use and denies over-budget calls in your own process — before they reach the provider, without routing prompt content through a hosted gateway.
Import, wrap, set a cap — three steps.
Runs inside your appProvider-direct callsMetadata-only dashboardOpen-source SDK
Budget Status
nightly-batch
your process
client = Solwyn(client)
client.chat.completions.create(…)
BudgetExceededError: Budget exceeded
for project nightly-batch
call not sent to provider
The next call was denied in your process — it never reached the provider.
Hard-deny is a single setting in your dashboard — alerts-only is the default, so nothing breaks until you flip it.
How runaway spend actually happens
Not stolen keys. Not your cloud bill. The spend that originates inside your own code — the only kind a local cap can stop.
The retry job with no ceiling.
A background job with no max-retry limit re-sent the same work until the developer noticed: “I assumed that not having a default meant there was a fixed number of retries, not infinite.” A daily cap ends this at your limit.
Triplett, micro.webology.dev, Nov 2025 — self-reported, named.
The agent stuck in a tool-call loop.
An assistant fell into a function-call loop: “burned $100 in a couple of hours… by the next morning, it burned another $160.” A hard-deny cap stops the loop at the cap, not at the refund.
OpenAI Developer Community, Dec 2023 — self-reported, guardrail code posted; OpenAI later credited the charges.
The pattern
Every runaway is the same shape: your code calls the model, the result triggers another call, and nothing in the loop knows to stop. The calls succeed, so no error fires — until something external intervenes.
The model kept answering because the code kept asking. Solwyn adds the stop condition.
Three steps between your agents and a runaway bill.
No new infrastructure. No gateway migration. No Solwyn-hosted proxy in the request path — just a wrapper around the client you already use.
Deploy an agent, cross your fingers, check the bill next month.
Deploy an agent whose next over-budget call is denied in your process, that fails over to your configured fallback, and that reports every dollar.
5K requests a month and one hard cap, free. No card.
What you get
The cap is just the start.
Set the limit before the damage starts.
Daily, weekly, or monthly budgets per project. Alerts fire by default, so your agents keep running while you get notified. Opt into hard-deny and over-budget calls stop in your process — before they ever reach the provider.
Budget Status
Team plan and up
When your provider goes down, your agents don't.
A local circuit breaker tracks provider health client-side — no network hop — and routes to your configured fallback automatically. The decision happens in your own process, with no server in the loop, so you don't get paged.
Provider Health
The agent burning money has a name.
Per-project cost breakdown by model and time period. Real-time spend vs. budget. Trend indicators that show you where costs are accelerating before they become a problem. All powered by usage metadata — prompt content is never sent to Solwyn.
Breakdown — by model
| Model | Share of cost | Requests | Tokens | Cost |
|---|---|---|---|---|
gpt-5.2OpenAI | 1,392 | 4,214,284 | $650.00 · 47% | |
claude-sonnet-4-5Anthropic | 732 | 3,196,428 | $410.71 · 30% | |
gpt-5-miniOpenAI | 1,464 | 8,964,284 | $171.43 · 12% | |
gemini-3-proGoogle | 350 | 2,246,428 | $158.93 · 11% | |
| Total · 4 models · 3 providers | 3,938 | 18,621,424 | $1,391.07 | |
Every channel on all paid plans
Text the founder. Page the on-call. Ping the Discord.
Email and SMS out of the box; Slack, Microsoft Teams, and PagerDuty for the eng team; Telegram and Discord for the community you run. Every channel ships on every paid plan — configure a destination once and reuse it across all your projects.
Notification Channels
founder@acme.dev
Webhook ****XXXX
Routing key ****R3y0
Webhook ****T3AM
Webhook ****D1SC
Bot token ****B0T9 · chat -1001234567890
Your prompts never touch our servers.
Not by policy. By architecture.
Solwyn runs inside your process — your LLM calls go straight to the provider, and we're never in the path.
- ✓Token count
- ✓Model
- ✓Latency
- ✓Status
- ✓Project ID
- ✓Tags you attach
- ✕Prompts
- ✕Responses
- ✕System messages
- ✕Function calls
- ✕Conversation history
- ✕Tool arguments & payloads
- ✕Your provider API keys
Audit exactly what leaves your process — read the open-source SDK →
We can't leak what we never had.
Choose the right control point
Keep the tools that help you see. Add Solwyn for the local financial stop.
Observability platforms help teams trace, evaluate, and improve AI behavior. Gateways centralize routing, access, and policy. Solwyn solves a narrower job: a project budget check inside your application process, before the next provider request.
Langfuse, LangSmith, Braintrust, Arize, Datadog
Best when: You need traces, datasets, evals, and quality monitoring. Keep it — Solwyn is not a replacement.
Portkey, Helicone, LiteLLM (hosted modes)
Best when: You want a managed central policy and routing layer. Model traffic traverses another managed control point.
LiteLLM, Portkey (self-hosted)
Best when: You want central control inside your own environment. Your team deploys, scales, and operates the gateway service.
Project budgets enforced in the application, while provider calls remain direct. Failover handled client-side. Only usage metadata reaches us — prompt content is never sent to Solwyn.
Use Langfuse, LangSmith, Braintrust, Arize, or Datadog for deep observability. Use Solwyn when the application itself needs to say “no more model calls for this project.”
Who it's for
Built for teams whose AI keeps running when nobody is watching.
- Production agents and tool-using workflows
- Queue workers, scheduled jobs, and batch generation
- Multi-provider apps that need local fallback
- Teams that want project-level cost boundaries
- Security-conscious teams avoiding a hosted prompt proxy
- A full tracing, evaluation, or prompt-management replacement
- A central enterprise gateway for every team and model
- A substitute for retry limits, timeouts, and app safeguards
Solwyn is one layer in a defense-in-depth design — keep your retry limits, step limits, and timeouts. It works alongside your observability stack, not instead of it.
Newly launched
Help shape the financial safety layer for production agents.
We are selecting ten launch partners running real AI workloads. You get a founder-led setup session, direct implementation support, a monthly product feedback call, and a 12-month price lock. We get candid usage feedback.
Prefer self-service? The free tier includes the hard cap.
BEST FIT: A PRODUCTION OR STAGING WORKLOAD WITH UNATTENDED MODEL CALLS
A loop won't wait for you to check the dashboard.
Wrap your client, set a cap, deploy. Three steps, and over-budget calls stop before they reach your provider. The free tier includes a hard cap — no card, no prompts transmitted.
Add a hard cap free30-day money-back guarantee on all paid plans. Refund policy